[
https://issues.apache.org/jira/browse/MESOS-1199?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14070994#comment-14070994
]
Ian Downes commented on MESOS-1199:
-----------------------------------
[~craig-mesos] I can shepherd any work on this if you'd like. How were you
thinking of doing this?
I committed code that made the process alive check much, much cheaper so I
think a viable approach to this problem could be as simple as reducing the
polling interval, e.g., from the current 1 second down to 100 or perhaps 50 ms.
The overhead to this should be characterized first.
> Subprocess is "slow" -> gated by process::reap poll interval
> ------------------------------------------------------------
>
> Key: MESOS-1199
> URL: https://issues.apache.org/jira/browse/MESOS-1199
> Project: Mesos
> Issue Type: Improvement
> Affects Versions: 0.18.0
> Reporter: Ian Downes
> Assignee: Craig Hansen-Sturm
>
> Subprocess uses process::reap to wait on the subprocess pid and set the exit
> status. However, process::reap polls with a one second interval resulting in
> a delay up to the interval duration before the status future is set.
> This means if you need to wait for the subprocess to complete you get hit
> with E(delay) = 0.5 seconds, independent of the execution time. For example,
> the MesosContainerizer uses mesos-fetcher in a Subprocess to fetch the
> executor during launch. At Twitter we fetch a local file, i.e., a very fast
> operation, but the launch is blocked until the mesos-fetcher pid is reaped ->
> adding 0 to 1 seconds for every launch!
> The problem is even worse with a chain of short Subprocesses because after
> the first Subprocess completes you'll be synchronized with the reap interval
> and you'll see nearly the full interval before notification, i.e., 10
> Subprocesses each of << 1 second duration with take ~10 seconds!
> This has become particularly apparent in some new tests I'm working on where
> test durations are now greatly extended with each taking several seconds.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
