I'm still looking into it. So far I have not seen the slowdown you have described, but will continue to try to figure out what's going on. I know this is inconvenient. We just haven't seen usage like this yet.
Christian -- Christian Hammond - chip...@chipx86.com Review Board - http://www.review-board.org VMware, Inc. - http://www.vmware.com On Mon, Mar 23, 2009 at 1:19 PM, ciaomary <ciaom...@gmail.com> wrote: > > Any follow up on this? Any configuration guidance? > > We've moved to a 16 G + 4 cpu system and still have unacceptable > response times (~30 seconds) for really large diffs with hundreds of > review comments. > > If you can't reproduce this, I recommend you set the number of diff > files per page from 20 to something really high (like 100) and then > post a review with the same number of files deleted. For us, this puts > a huge load on the local browser and the server VM during load. > > On Mar 19, 12:41 pm, ciaomary <ciaom...@gmail.com> wrote: > > Thanks again. I'm really not that familiar with Apache 2 w/ regards to > > performance issues. At this time, I just have a more or less out-of- > > the-box Apache2 setup on CentOS 5. Any recommendations here would be > > hugely appreciated. Further answers inline below... > > > > On Mar 19, 12:09 pm, Christian Hammond <chip...@chipx86.com> wrote: > > > > > We should figure out first why your backend server is being hit so > hard. We > > > have over a thousand people at VMware submitting good sized diffs and > aren't > > > hitting any of these issues. So a few more questions. Apologies if > you've > > > answered these before in other threads. > > > > > 1) What MPM is your Apache using? > > > > I'm using the default for httpd 2.2.3 CentOS. I believe this is > > 'prefork'. > > > > > 2) And is this fastcgi or mod_python? > > > > mod_python (mod_python-3.2.8-3.1) > > > > > 3) Are you absolutely sure Review Board is using your memcached server? > Go > > > in the admin dashboard and click Server Cache, then copy and paste the > info > > > and paste it here. > > > > Server Cache > > Cache backend: django.core.cache.backends.memcached > > Statistics > > 127.0.0.1:11211 Memory usage: 45.7 MB > > Keys in cache: 1767 of 1777 > > Cache hits: 3996 of 7464: 53% > > Cache misses: 3468 of 7464: 46% > > Cache evictions: 0 > > Cache traffic: 46.1 MB in, 103.8 MB out > > Uptime: 53009 > > > > > > > > > > > > > We might be able to do something smarter with deleted diffs, but that > would > > > require a good bit of work, and we'd have to think carefully about it. > > > > > We talked about splitting up the reviews page, but decided it wouldn't > make > > > much sense due to how it's ordered. We came up with a method for > collapsing, > > > but I'm probably holding off until after 1.0 to finish this, because > it > > > needs a lot more thought and testing. > > > > > Christian > > > > > -- > > > Christian Hammond - chip...@chipx86.com > > > Review Board -http://www.review-board.org > > > VMware, Inc. -http://www.vmware.com > > > > > On Thu, Mar 19, 2009 at 11:39 AM, ciaomary <ciaom...@gmail.com> wrote: > > > > > > Thanks for your response. Please see comments inline below... > > > > > > On Mar 18, 11:35 am, Christian Hammond <chip...@chipx86.com> wrote: > > > > > Not immediately, no. > > > > > > > I can't even determine right now whether we can do anything about > this. > > > > > You're seeing crazy CPU loads that we're definitely not seeing, and > most > > > > of > > > > > this has to do with the browser itself. We're loading the files > > > > > asynchronously, but it appears that for whatever reason your > browser is > > > > > blocking until it's all loaded (if I'm understanding right). > > > > > > Just for clarity, the page can sometimes load partially, but since > the > > > > CPU is at 99% it's of little value. I don't get the CPU back until > the > > > > page is fully loaded. > > > > > > We now understand that our backend server is also getting maxed out > to > > > > the point of failure. One request of this page demands 800 M of > > > > virtual memory from Apache! Once the request is fully loaded, 400 M > of > > > > that memory is freed again - but since we have 200 reviewboard users > > > > this isn't very scalable. > > > > > > > I'm wondering > > > > > if there's something with the configuration in your browsers where > you > > > > work > > > > > that is causing some of this. > > > > > > I really don't think this is a browser configuration issue because > > > > users across many different OS and browsers are seeing this. I see it > > > > on default FireFox 3.0.7 and IE 7.0. Users have reported that Safari > > > > works the best, but I have not confirmed. FireFox 2 and IE 6 users > > > > have reported the same problem. > > > > > > > You say this is happening on several different browsers? In the > case of > > > > > Firefox, what extensions are loaded? > > > > > > Just the default FireFox 3.0.7 install. > > > > > > > We definitely would like to fix this. But we just don't know enough > about > > > > > what the problem is right now to determine if it's in our control. > > > > > > Apache must load up a huge amount of data in VM for these large diffs > > > > (I believe this is especially true when diffs contain deleted files). > > > > This isn't scalable across many users. Can the amount of data/ > > > > filediffs/etc needed to load the page be scaled back further? > Changing > > > > the 'Paginate by' value from 20 to 3 has helped, but not enough and > it > > > > hasn't helped the review page obviously. > > > > > > Instead of showing all lines for deleted files can this be loaded > > > > later only on request? > > > > Can the 'View Reviews' page be broken up or paginated as well? > > > > I think these two suggestions would help us. > > > > > > > Christian > > > > > > > -- > > > > > Christian Hammond - chip...@chipx86.com > > > > > Review Board -http://www.review-board.org > > > > > VMware, Inc. -http://www.vmware.com > > > > > > > On Wed, Mar 18, 2009 at 9:54 AM, ciaomary <ciaom...@gmail.com> > wrote: > > > > > > > > Can anything be done to fix the pegged CPU issue I've reported in > my > > > > > > prior email? > > > > > > > > On Mar 17, 9:38 am, ciaomary <ciaom...@gmail.com> wrote: > > > > > > > The downloadable diff for the review is 1.6MB. > > > > > > > > > The review has 138 different files (7 pages). > > > > > > > > > Page 1 loads in ~1 minute in FireFox. The twenty files are on > average > > > > > > > 38 K. (max=118K, min=2K). Here all files have edit changes (no > > > > deleted > > > > > > > files.) > > > > > > > > > Page 3 loads in ~3 minutes in FireFox. The twenty files are on > > > > average > > > > > > > 25K . No major deviations from the average. Here 12 of the > files have > > > > > > > been deleted rather than just edited. > > > > > > > > > There are hundreds of review comments on this review across > many > > > > users > > > > > > > and files. > > > > > > > > > During page load, the CPU is pegged and the browser is > unresponsive > > > > > > > for a good 2-3 minutes. This is the cause every time, very > > > > > > > reproducable. If you are patient the page finally loads and the > > > > system > > > > > > > CPU returns to normal. > > > > > > > > > FireBug shows an HTTPS GET request for each of the twenty files > > > > during > > > > > > > the slow down/cpu pegging. Each HTTPS GETS are taking longer on > page > > > > > > > 3, with some taking up to 2.5 seconds (others < 50ms). Since > the is > > > > > > > cpu is pegged the browser processing seems to be the cause of > the > > > > > > > delay however. > > > > > > > > > On Mar 16, 6:31 pm, Christian Hammond <chip...@chipx86.com> > wrote: > > > > > > > > > > So it's really going to depend on the sizes of the individual > files > > > > > > > > themselves. If a file is by itself large enough to cause a > couple > > > > meg > > > > > > diff > > > > > > > > to be generated, there's nothing we can do really do, since > that > > > > boils > > > > > > down > > > > > > > > to too large a file to show in the browser. > > > > > > > > > > In your page 3 example, how big are the files and the diffs > in > > > > > > particular? > > > > > > > > > > The page itself loads quick enough, right? It's just the diff > > > > > > fragments? > > > > > > > > Which ones are you finding takes a long time and how big are > those > > > > > > changes? > > > > > > > > > > Christian > > > > > > > > > > -- > > > > > > > > Christian Hammond - chip...@chipx86.com > > > > > > > > Review Board -http://www.review-board.org > > > > > > > > VMware, Inc. -http://www.vmware.com > > > > > > > > > > On Mon, Mar 16, 2009 at 5:32 PM, mary <ciaom...@gmail.com> > wrote: > > > > > > > > > > > On really large diffs, performance is very slow and can > crash the > > > > > > > > > browser. > > > > > > > > > > > We've picked up the recent 3/13/09 nightly which has helped > > > > > > enormously > > > > > > > > > (A BIG THANKS!) but that said, we're still finding pages > that > > > > take 3+ > > > > > > > > > minutes to load. > > > > > > > > > > > For example.... we have one review in particular that has > File > > > > > > Changes > > > > > > > > > spread over 6 ReviewBoard pages. Page 3 takes on average 3+ > > > > minutes > > > > > > to > > > > > > > > > load. It also readily crashes my browser - pegging my CPU > and I > > > > have > > > > > > > > > to kill the session. (URL= > > > >https://reviewboard/r/2808/diff/?page=3). > > > > > > > > > This is in FireFox 3.0.7. Under IE the page doesn't load > without > > > > > > > > > running into script errors. Unfortunately, these large > > > > ReviewBoard > > > > > > > > > diffs are a typical use case at our company (typically when > large > > > > > > > > > merges are done) and breaking things across more than 10 > reviews > > > > jsut > > > > > > > > > isn't plausible. I should mention that not only are the > diff > > > > > > fragments > > > > > > > > > themselves large for these use cases but the number of > reviewers > > > > and > > > > > > > > > comments gets to be very large too. We're maxing out what > > > > ReviewBoard > > > > > > > > > can handle on all fronts. > > > > > > > > > > > Can further investigation be done into these performance > issues > > > > for > > > > > > > > > us? I will supply further information as I collect it. > > > > > > > > > > > Thanks, > > > > > > > > > Mary- Hide quoted text - > > > > > > > > > > - Show quoted text -- Hide quoted text - > > > > > > > > > - Show quoted text -- Hide quoted text - > > > > > > > - Show quoted text -- Hide quoted text - > > > > > - Show quoted text -- Hide quoted text - > > > > - Show quoted text - > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "reviewboard" group. 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