Re: Intent to remove: the 'Memory usage of Subprocesses' table from about:performance
+1 for adding it back in the future. Even if memory usage isn't as directly related to performance as CPU usage is, it has a *huge* effect on performance on memory constrained systems, if it causes them to have to swap. Also, in my experience, the overlap between poorly-performing code and leaky code tends to be high, so it would really be nice to keep these numbers in one place. On Thu, Jul 12, 2018 at 10:25:31AM -0700, Eric Rahm wrote: Thanks Florian, considering it's roughly unmaintained right now, leaking, and showing up in perf profiles it sounds reasonable to remove the memory section. I've filed bug 1475301 [1] to allow us to measure USS off main thread; we can deal with adding that back in the future if it makes sense. -e [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1475301 On Thu, Jul 12, 2018 at 12:41 AM, Florian Quèze wrote: On Thu, Jul 12, 2018 at 1:18 AM, Eric Rahm wrote: > What performance issues are you seeing? RSS and USS should be relatively > lightweight and the polling frequency isn't very high. It seems ResidentUniqueDistinguishedAmount does blocking system calls, resulting in blocking the main thread for several seconds in the worst case. Here's a screenshot of a profile showing it: https://i.imgur.com/DjRMQtY.png (unfortunately that profile is too big and fails to upload with the 'share' feature). There's also a memory leak in the implementation, after leaving about:performance open for a couple hours, there was more than 300MB of JS "Function" and "Call" objects (about:memory screenshot: https://i.imgur.com/21YNDru.png ) and the devtools' Memory tool shows that this is coming from the code queuing updates to that subprocess memory table: https://i.imgur.com/04M71hg.png Florian -- Florian Quèze ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform -- Kris Maglione Senior Firefox Add-ons Engineer Mozilla Corporation If we wish to count lines of code, we should not regard them as lines produced but as lines spent. --Edsger W. Dijkstra ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
Re: Intent to remove: the 'Memory usage of Subprocesses' table from about:performance
Thanks Florian, considering it's roughly unmaintained right now, leaking, and showing up in perf profiles it sounds reasonable to remove the memory section. I've filed bug 1475301 [1] to allow us to measure USS off main thread; we can deal with adding that back in the future if it makes sense. -e [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1475301 On Thu, Jul 12, 2018 at 12:41 AM, Florian Quèze wrote: > On Thu, Jul 12, 2018 at 1:18 AM, Eric Rahm wrote: > > > What performance issues are you seeing? RSS and USS should be relatively > > lightweight and the polling frequency isn't very high. > > It seems ResidentUniqueDistinguishedAmount does blocking system calls, > resulting in blocking the main thread for several seconds in the worst > case. Here's a screenshot of a profile showing it: > https://i.imgur.com/DjRMQtY.png (unfortunately that profile is too big > and fails to upload with the 'share' feature). > > There's also a memory leak in the implementation, after leaving > about:performance open for a couple hours, there was more than 300MB > of JS "Function" and "Call" objects (about:memory screenshot: > https://i.imgur.com/21YNDru.png ) and the devtools' Memory tool shows > that this is coming from the code queuing updates to that subprocess > memory table: https://i.imgur.com/04M71hg.png > > Florian > > -- > Florian Quèze > ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
Re: Intent to remove: the 'Memory usage of Subprocesses' table from about:performance
On Thu, Jul 12, 2018 at 1:18 AM, Eric Rahm wrote: > What performance issues are you seeing? RSS and USS should be relatively > lightweight and the polling frequency isn't very high. It seems ResidentUniqueDistinguishedAmount does blocking system calls, resulting in blocking the main thread for several seconds in the worst case. Here's a screenshot of a profile showing it: https://i.imgur.com/DjRMQtY.png (unfortunately that profile is too big and fails to upload with the 'share' feature). There's also a memory leak in the implementation, after leaving about:performance open for a couple hours, there was more than 300MB of JS "Function" and "Call" objects (about:memory screenshot: https://i.imgur.com/21YNDru.png ) and the devtools' Memory tool shows that this is coming from the code queuing updates to that subprocess memory table: https://i.imgur.com/04M71hg.png Florian -- Florian Quèze ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
Re: Intent to remove: the 'Memory usage of Subprocesses' table from about:performance
This was added in bug 1255843 [1]. I don't feel to strongly about keeping it around, I believe mconley and mrbkap came up with the idea of adding it. It's *much* more lightweight than about:memory and provides automatic updates which is nice for monitoring without external tools. What performance issues are you seeing? RSS and USS should be relatively lightweight and the polling frequency isn't very high. -e [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1255843 On Wed, Jul 11, 2018 at 11:12 AM, Florian Quèze wrote: > Context: we are currently redesigning about:performance to make it > more useful for users. > > This section of the current about:performance page provides > information that isn't actionable for users, and collecting this > information causes performance issues, so I think it's time to remove > it. > > I filed https://bugzilla.mozilla.org/show_bug.cgi?id=1474990 for the > removal. > > If someone uses this information and strongly thinks we should keep it > (eg. by moving it to about:memory), now is the time to speak up. > > Thanks, > Florian > > -- > Florian Quèze > ___ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform > ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
Intent to remove: the 'Memory usage of Subprocesses' table from about:performance
Context: we are currently redesigning about:performance to make it more useful for users. This section of the current about:performance page provides information that isn't actionable for users, and collecting this information causes performance issues, so I think it's time to remove it. I filed https://bugzilla.mozilla.org/show_bug.cgi?id=1474990 for the removal. If someone uses this information and strongly thinks we should keep it (eg. by moving it to about:memory), now is the time to speak up. Thanks, Florian -- Florian Quèze ___ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
