XYZZY IDLE TIMER CODE
XYZZY IDLE TIMER PLUS

It could just be non-localized, plaintext, IMO. IвЂ™d put it in a separate page - about:logging or something - because it doesnвЂ™t have to be only memory-related events.

Instead of dumping the buffer to disk I would display its contents on about:memory So you could make it quite big if you wanted to run the browser for a long time and not miss events. Perhaps there could be a command-line option or about:config option to increase its size. вЂ“ Create/destroy a JSCompartment, including the principle (the URL, basically)ДЄnd I think the in-memory circular buffer is a good idea, with a way of saving it to disk. Some other events that would be interesting: I donвЂ™t think it has to be restricted to memory-related events, though obviously they are good to have in there. Instead of dumping the buffer to disk I would display its contents on about:memory вЂ“ the user should attach about:memory contents to the bug report anyway.

XYZZY IDLE TIMER PLUS

Two sprintfs per second plus a 64k circular buffer is probably Second in the log, weвЂ™re misusing the mechanism. If weвЂ™re putting more than one or two lines per ItвЂ™s most valuableД®xactly when memory use is unexpectedly high and we have no clear idea I think it should be enabled by default, though. I would suggest keeping the log in a buffer instead of writing it to a file, to reduce the overhead (otherwise IвЂ™m afraid itвЂ™s going to be too expensive for me) and/or maybe have it disabled by default (settable at runtime) as people know when they want it.Д«jacob: keeping it in a buffer is important, since writingД¬ontinuously to disk could cause large numbers of otherwise-pointlessДisk wakeups on mobile systems, which is definitely bad. I think that would be a good idea, and I can see how I would use it. I think that could be interesting, and that this should probably be part of the recently born telemetry. But AFAIK thereвЂ™s no uniform, system-wide, lightweight, easy-to-use mechanism. ThereвЂ™s, for example, and IвЂ™m sure other subsystems have their own schemes. Partial implementations of this exist already. Then, when someone reports excessive memory use, the first thing we ask for is the log file. Perhaps a moderate sized circular buffer (64KB? 1MB?) that could be dumped to disk on request. For sure we donвЂ™t want to log more than a couple of events per second. The log would be low overhead, so it can be used in production. That way, weвЂ™d at least have some information about the space history leading up to a situation where a user says вЂњurk! massive memory leak!вЂќ.

user requested about:memory (+ what it produced).

new tab created now there are 23 of them.

downloaded another chunk of the phishing database.

Perhaps with some indirectly relevant events such as

XYZZY IDLE TIMER CODE

nanojit / mjit mapped / unmapped code pages.jemalloc mmapвЂ™d more pages / munmapped some pages.CC started / ended, total size N, reclaimed M bytes.GC started / ended, total size N, reclaimed M bytes.Nothing heavyweight, just one line per event, timestamped, plus brief relevant stats. So the idea is simple: make a log file listing events which are known to have a significant impact on memory usage. Meanwhile the original reporter gets bored with the discussion and moves on to something else, and thereвЂ™s general confusion, annoyance, and lack of reproducibility all round. This goes on and on, while everybody tries to figure out what Firefox was actually doing in the period leading up to the too-much-memory observation. First, the user reports that вЂњI did A, B and C, had a coffee, went back to my machine and found that Firefox was sitting on N gigabytes of memory.вЂќ Then follows lots ofДiscussion along the lines of вЂњoh, so the cycle collector did/didnвЂ™t run while Fx was idleвЂќ, and вЂњbut no, thatвЂ™s not right, because the tertiary FooBar timer inhibit mechanism will have made the XYZ collector run insteadвЂќ kind of thing. It seems to me that many end-user bugzilla reports about excessive memory use share a common structure.

Xyzzy idle timer