[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=17631325#comment-17631325 ] Michael Semb Wever commented on CASSANDRA-7486: --- Created CASSANDRA-18027 instead of re-opening this. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Local/Config >Reporter: Jonathan Ellis >Priority: Normal > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian Jira (v8.20.10#820010) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=17631321#comment-17631321 ] Michael Semb Wever commented on CASSANDRA-7486: --- Patch at https://github.com/apache/cassandra/compare/trunk...thelastpickle:cassandra:mck/7486/trunk > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Local/Config >Reporter: Jonathan Ellis >Priority: Normal > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian Jira (v8.20.10#820010) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[
https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14902754#comment-14902754
]
Benedict commented on CASSANDRA-7486:
-
Get this running on blade_11b...
{code}
raceback (most recent call last):
File "/home/ryan/git/cstar_perf/env/bin/cstar_perf_stress", line 9, in
load_entry_point('cstar-perf.tool==1.0', 'console_scripts',
'cstar_perf_stress')()
File "/home/ryan/git/cstar_perf/tool/cstar_perf/tool/stress_compare.py", line
258, in main
stress_compare(**cfg)
File "/home/ryan/git/cstar_perf/tool/cstar_perf/tool/stress_compare.py", line
111, in stress_compare
stress_shas = setup_stress(stress_revisions)
File "/home/ryan/git/cstar_perf/tool/cstar_perf/tool/benchmark.py", line 406,
in setup_stress
revisions.update(build_stress(stress_revision))
File "/home/ryan/git/cstar_perf/tool/cstar_perf/tool/benchmark.py", line 382,
in build_stress
raise AssertionError('Invalid stress_revision: {}'.format(stress_revision))
AssertionError: Invalid stress_revision: enigmacurry/stress-report-interval
{code}
Is the new code only deployed to blade_11, perhaps?
> Migrate to G1GC by default
> --
>
> Key: CASSANDRA-7486
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7486
> Project: Cassandra
> Issue Type: New Feature
> Components: Config
>Reporter: Jonathan Ellis
> Fix For: 3.0 alpha 1
>
>
> See
> http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning
> and https://twitter.com/rbranson/status/482113561431265281
> May want to default 2.1 to G1.
> 2.1 is a different animal from 2.0 after moving most of memtables off heap.
> Suspect this will help G1 even more than CMS. (NB this is off by default but
> needs to be part of the test.)
--
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[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14902802#comment-14902802 ] Ryan McGuire commented on CASSANDRA-7486: - The code was deployed, but the git fetch didn't work. We'll fix that. I manually fetched from my repo, so it'll work with that stress revision for now. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14900267#comment-14900267 ] Pavel Yaskevich commented on CASSANDRA-7486: Thanks, Benedict! This is in line with what I would expect from longer run of CMS vs. G1 since CMS is known to degrade over time and G1 actually needs some time to collect statistics and properly arrange relocations etc., so let's wait with revert and see what would 100x larger run produce. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14901846#comment-14901846 ] Ryan McGuire commented on CASSANDRA-7486: - [~benedict] I modified the schedule GUI to allow you to change the version of stress per operation. Just change the default 'apache/trunk' to 'enigmacurry/stress-report-interval' where I took your branch and applied a 4G stress heap. If you want to tweak that, you can put your own branch name in instead. The GC logs have been logged for awhile now, they're wrapped up in the same tarball as the other logs that you can download. See this example for how to specify your test: http://cstar.datastax.com/schedule?clone=0c2efd50-60d5-11e5-b6a8-42010af0688f > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14900842#comment-14900842 ] Benedict commented on CASSANDRA-7486: - Regrettably, that run crashed. Will have to diagnose the logs to see what may have happened - [~EnigmaCurry], could you unstick the cstar job, and collect the log files? > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14900957#comment-14900957 ] Jeremy Hanna commented on CASSANDRA-7486: - I was kind of curious about whether 2.1 or 2.2 branches exhibited the same behavior with the same gc settings as other data points. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14900923#comment-14900923 ] Ryan McGuire commented on CASSANDRA-7486: - Here's the logs: http://scp.datastax.com/~ryan/cstar_perf/01b714d8_logs.tar.bz2 > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14901127#comment-14901127 ] Benedict commented on CASSANDRA-7486: - [~enigmacurry]: could you upgrade stress to run from [this branch|https://github.com/belliottsmith/cassandra/tree/stress-report-interval]? Could you also ensure it's running with a largeish heap (at least a couple of Gb)? I'll file tickets to update the mainline source tree on both these counts. We should start enabling stress gc logging in cstar at some point as well, so we can diagnose issues in the run, and see if they're attributable to stress itself. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14899937#comment-14899937 ] Benedict commented on CASSANDRA-7486: - bq. [here is one|http://cstar.datastax.com/graph?stats=2611ee46-5ee4-11e5-a4e4-42010af0688f=op_rate=1_user=1_aggregates=true=0=9028.03=0=146633.3] 10x larger and another 100x larger [is still running|http://cstar.datastax.com/tests/id/01b714d8-5f32-11e5-a4e4-42010af0688f] Interestingly, the completed 10x larger is a more nuanced picture, but this is because CMS got slower for one of the runs, not G1GC faster - but it never got up to its prior speed - this is weird, since 2.2 did manage to get up to its faster speed still, so there may be something funny going on on that particular test. bq. It seems that the max heap is still 8G in trunk so maybe it is unfair for G1. What is the heap size of these tests? I'm not sure I would call that unfair. These boxes have no more than 64Gb of RAM, I'm pretty sure (perhaps only 32Gb), and so for anything but the most write-heavy workloads an 8Gb heap is probably what you'll want to ensure the file cache can make meaningful contributions to performance. Certainly we can and should test more scenarios, but this is a pretty typical setup for a pretty typical piece of hardware. We should consider giving users profiles for different workloads, though, and consider raising the max heap much higher for write-heavy workloads, or boxes with gigantic banks of RAM, and use G1 accordingly (as driven by our research) > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877316#comment-14877316 ] Jonathan Shook commented on CASSANDRA-7486: --- This seems pretty open-and-shut where I would expect a bit more of a nuanced test. We've honestly seen G1 be the operative improvement in some cases in the field. I'd much prefer to see "needs more analysis" than to see it resolved as fixed. CMS will *not* scale with hardware as we go forward. This is not in debate. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877420#comment-14877420 ] Pavel Yaskevich commented on CASSANDRA-7486: It would be interesting to know what happens in the longer running test, more than 10 minutes let's say, if there is a way to run it... > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Benedict > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877434#comment-14877434 ] Phil Yang commented on CASSANDRA-7486: -- It seems that the max heap is still 8G in trunk so may be it is unfair for G1. What is the heap size of these tests? i > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Benedict > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877432#comment-14877432 ] Jonathan Shook commented on CASSANDRA-7486: --- I'd argue that there already is an increase in pain as you try to use more of the metal on a node. We've just become acclimated to it. Instead of scaling the compute side over the metal, we do silly things like run multiple instances per box. Its not really silly if it gets results, but it is an example of where we do something tactically, get so used to it as a necessary complexity, and then just keep taking for granted that this is how we do it. I personally don't want to keep going down this path. So, I am inclined to carry on with the testing and characterization, in time. We should compare notes and methods and see what can be done to reduce the overall effort. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Benedict > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877411#comment-14877411 ] Jonathan Shook commented on CASSANDRA-7486: --- I do believe that there is a gap between the maximum effective CMS heap sizes and the minimum effective G1 sizes. I'd estimate it to be about the 14GB - 24GB range. Neither does admirably when taxed for GC throughput in that range. Put in another way, I've never and would never advocate that someone use G1 with less than 24G of heap. In practice, I use it only on systems with 64GB of memory, where it is no big deal to give G1 32GB to work with. We have simply seen G1 go slower when it doesn't have adequate scratch space. In essence, it really likes to have more memory. We have also seen anecdotal evidence that G1 seems to settle in, performance wise, after a warm-up time. It could be that it needs to collect metrics long enough under steady state before it learns how to handle GC and heap allocation better. This hasn't been provided definitively, but is strongly evidenced in some longer-run workload studies. I do agree that when you don't really need more than 12GB of heap, CMS will be difficult to beat with the appropriate tunings. I'm not really sure what to do about the mid-band where neither CMS nor G1 are very happy. We may have to be prescriptive in the sense that if you want to use G1, then you should give it enough to work with effectively. Perhaps we need to make the startup scripts source a different GC config file depending on the detected memory in the system. I normally configure G1 as a sourced (included) file to the -env.sh script, so this would be fairly straightforward. [~ato...@datastax.com], any comments on this? > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877404#comment-14877404 ] Benedict commented on CASSANDRA-7486: - bq. Is the picture equally bleak at RF=3? [Regrettably so|http://cstar.datastax.com/graph?stats=a1eee43a-5f32-11e5-88b3-42010af0688f=op_rate=3_user=1_aggregates=true=0=112.2=0=163663.5] bq. Do the "2.2 GC" settings include anything other than the defaults from cassandra-env.sh? "ps -efw" output is sufficient. I haven't double checked, I simply copied [~tjake]'s branch and rebased to latest 3.0. It looks like it's just 2.2 defaults. bq. I'd be happy to take a look at the GC logs if they are available. The thing is, as I say, the _GC_ burden is pretty consistently lower. However the application performance is also worse. Indicating the problem isn't the collections, but the VM behavioural changes required to enable G1GC. So analyzing GC logs is unlikely to deliver much, and figuring out how to modify the application to reduce the burden here is unlikely to be a short task (if achievable). bq. This is not in debate. I'm afraid nothing is not in debate in this world :) If you mean to say "CMS will *not* scale with _increasingly gigantic heap sizes_" then we would probably be in agreement, however with smallish heaps CMS works just fine - better, even. If the mid-to-long term goal of Cassandra is to have a constant heap burden, i.e. decouple heap requirements from dataset, then it doesn't follow that increasing hardware capabilities requires G1GC. There are lots of reasons why this _should_ be our goal, and my understanding is there is a general consensus on that, but that's a separate debate. Certainly we need to do more research, but I will prognosticate briefly: I suspect we will find that with very large heaps (16Gb+) and with lots of headroom G1GC begins to outperform CMS, especially wrt the most critical of metrics, 99.9%ile. However I suspect we will find CMS continues to dominate in domains where it can maintain sufficiently low pause times. Since many users target the more modest heap sizes, we may find that it makes most sense to provide two default configurations, and have the user opt into our "default" G1GC settings if they intend to run with a very large heap. If, after extensive research, we find that we can confidently predict configs where it makes more sense, we should consider doing this automatically in cassandra-env. My suspicion is we won't manage to do this research in time for GA, but that doesn't stop us providing the parallel defaults and documentation to make it easy for users to enable it. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877418#comment-14877418 ] Albert P Tobey commented on CASSANDRA-7486: --- The main point of switching to G1 was to enable most users to get decent - if not the best - performance out of the box without having to guess HEAP_NEWSIZE. Since nobody has the time or inclination to test/discover further, it might as well be rolled back. Users won't notice any difference in pain since there was never a release with G1. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877419#comment-14877419 ] Benedict commented on CASSANDRA-7486: - Sounds like we're broadly in agreement then. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14877311#comment-14877311 ] Albert P Tobey commented on CASSANDRA-7486: --- Is the picture equally bleak at RF=3? Do the "2.2 GC" settings include anything other than the defaults from cassandra-env.sh? "ps -efw" output is sufficient. I'd be happy to take a look at the GC logs if they are available. > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=14747334#comment-14747334 ] Sebastian Martinka commented on CASSANDRA-7486: --- For future tests you could use logstash and kibana to generate graphs from G1 and CMS logs: https://github.com/Mortinke/logstash-pattern > Migrate to G1GC by default > -- > > Key: CASSANDRA-7486 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 > Project: Cassandra > Issue Type: New Feature > Components: Config >Reporter: Jonathan Ellis >Assignee: Albert P Tobey > Fix For: 3.0 alpha 1 > > > See > http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning > and https://twitter.com/rbranson/status/482113561431265281 > May want to default 2.1 to G1. > 2.1 is a different animal from 2.0 after moving most of memtables off heap. > Suspect this will help G1 even more than CMS. (NB this is off by default but > needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14562958#comment-14562958 ] Jonathan Ellis commented on CASSANDRA-7486: --- Yes, irc discussion. Basically options are to try to exhaustively test the hell out of it in the lab or to throw it over the wall and let users test it. Since we don't have the resources for the former, and the latter is pretty low risk (you can always copy back in the 2.2 defaults yourself), and we have pretty solid evidence from early adopters that it's an improvement in the real world, we are going with the latter rather than continuing to sit on it. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14562936#comment-14562936 ] Joshua McKenzie commented on CASSANDRA-7486: bq. My point is, we don't really fully understand G1, and unless we undertake a research project to fully understand its pathological cases, and how they compare/contrast to its history, I'd prefer we ensured it behaved under complex loads, and not just under isolated read or write loading. bq. Al, we're on board with making G1 the default for 3.0 (which incidentally requires java 8), if you can post a patch. [~benedict] and [~jbellis]: Reconcile these two statements for me as there don't appear to be updates on this ticket that bridge them. Were there discussions on IRC / offline or do you still have outstanding concerns about pathological cases w/this collector Benedict? Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14563034#comment-14563034 ] Joshua McKenzie commented on CASSANDRA-7486: Seems reasonable to me and glad to have that documented in the ticket (hint hint). Last question I have before commit is for [~ato...@datastax.com] (though anyone's welcome to chime in): Why did we settle on 500ms for our MaxGCPauseMillis? Was that also part of an offline conversation, or are we just rolling with the #'s Michael used above? Do we have any test data to show that 500 is a solid default for our use case rather than the pre-packaged 200 for g1 or the 2000 you'd used above for some testing? Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14563219#comment-14563219 ] Albert P Tobey commented on CASSANDRA-7486: --- I tested a number of different pause targets on a wide variety of machines. While the 200ms default is often fine on big machines with real CPUs, in Ghz-constrained environments like EC2 PVM or LV Xeons, throughput dropped considerably so that the GC could hit the pause target. I initially tested at 1000ms and 2000ms but settled on 500ms because it provides most of the benefit of a more generous pause target while being far enough below the current read/write timeouts in cassandra.yaml to make sure that pauses never/rarely hit those limits. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14561432#comment-14561432 ] Albert P Tobey commented on CASSANDRA-7486: --- Updated patches with spelling and whitespace fixes: https://github.com/tobert/cassandra/commits/g1gc-2 https://github.com/tobert/cassandra/commit/419d39814985a6ef165fdbafee5f1b84bf2f197b https://github.com/tobert/cassandra/commit/89d40af978eaeb02185726a63257d979111ad317 https://github.com/tobert/cassandra/commit/0f70469985d62aeadc20b41dc9cdc9d72a035c64 Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14561319#comment-14561319 ] Joshua McKenzie commented on CASSANDRA-7486: Sanity check on local laptop on a variety of workloads looks comparable between CMS and G1, slight edge to CMS but I'm on a sub 8G heap so that's to be expected. Couple of spelling nits in comments in conf: misspelled effecitve vice versa, not visa-versa Haven't tested yet on CI as I have a dtest going I don't want to mess with but I'm comfortable moving forward w/the results from testing locally. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14561318#comment-14561318 ] Joshua McKenzie commented on CASSANDRA-7486: Sanity check on local laptop on a variety of workloads looks comparable between CMS and G1, slight edge to CMS but I'm on a sub 8G heap so that's to be expected. Couple of spelling nits in comments in conf: misspelled effecitve vice versa, not visa-versa Haven't tested yet on CI as I have a dtest going I don't want to mess with but I'm comfortable moving forward w/the results from testing locally. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14560200#comment-14560200 ] Albert P Tobey commented on CASSANDRA-7486: --- https://github.com/tobert/cassandra/commit/0759be3b2a2a8ded0098622dcb95c0eb47d79fd3 Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14559769#comment-14559769 ] Joshua McKenzie commented on CASSANDRA-7486: We also need to update conf/cassandra-env.ps1 and bin/cassandra.ps1 to keep Windows' configuration in parity with linux on this ticket; the linked branches appear to be linux env only. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14559851#comment-14559851 ] Albert P Tobey commented on CASSANDRA-7486: --- Yeah. I started on the Powershell scripts but figured I should talk to someone more knowledgeable on Windows before making the change. If you want a straight port I can throw that together and do a quick test on my local Windows machine. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14559852#comment-14559852 ] Albert P Tobey commented on CASSANDRA-7486: --- Yeah. I started on the Powershell scripts but figured I should talk to someone more knowledgeable on Windows before making the change. If you want a straight port I can throw that together and do a quick test on my local Windows machine. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14559853#comment-14559853 ] Albert P Tobey commented on CASSANDRA-7486: --- Yeah. I started on the Powershell scripts but figured I should talk to someone more knowledgeable on Windows before making the change. If you want a straight port I can throw that together and do a quick test on my local Windows machine. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-7486) Migrate to G1GC by default
[ https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14559877#comment-14559877 ] Joshua McKenzie commented on CASSANDRA-7486: If you can throw together and link a branch with a straight port I'll do some quick sanity testing on it both locally and on the CI server. For changing JVM params it should be really straightforward. Migrate to G1GC by default -- Key: CASSANDRA-7486 URL: https://issues.apache.org/jira/browse/CASSANDRA-7486 Project: Cassandra Issue Type: New Feature Components: Config Reporter: Jonathan Ellis Assignee: Albert P Tobey Fix For: 3.0 beta 1 See http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning and https://twitter.com/rbranson/status/482113561431265281 May want to default 2.1 to G1. 2.1 is a different animal from 2.0 after moving most of memtables off heap. Suspect this will help G1 even more than CMS. (NB this is off by default but needs to be part of the test.) -- This message was sent by Atlassian JIRA (v6.3.4#6332)
