Memory usage regression

Rich Prohaska prohaska7 at
Tue Nov 6 07:26:27 PST 2012

I assume that the green (patched vm rss) and purple (mozjemalloc vm
rss) lines overlay each other.  The graph is hard to read.

On Mon, Nov 5, 2012 at 2:17 AM, Mike Hommey <mh+jemalloc at> wrote:
> On Sun, Nov 04, 2012 at 09:17:32PM -0800, Jason Evans wrote:
>> On Nov 1, 2012, at 12:23 PM, Jason Evans wrote:
>> > On Oct 31, 2012, at 12:00 AM, Mike Hommey wrote:
>> >>
>> >> It's unfortunately only slightly better.
>> >>
>> >
>> > Thanks for testing it.  Too bad it didn't help.
>> >
>> > I spent some time yesterday thinking about the clean vs. dirty run
>> > fragmentation problem yesterday and came to realize that up to now
>> > all of the dirty page purging strategies jemalloc has employed have
>> > been about limiting RSS, with only indirect regard for VM size.  I
>> > developed a patch that actually tracks the amount of clean/dirty run
>> > fragmentation, but I'm still working out how to act on the
>> > information.
>> I finally managed to experiment a bit with the aforementioned patch,
>> and it looks reasonably good (chunk fragmentation is *way* down).  I'm
>> seeing a higher soft page fault rate with this patch in place, but the
>> patch and the control appear to be converging as the experiments run,
>> so the fragmentation reduction may have some positive performance
>> effects that mitigate the cost of extra purging.
> This patch works quite well. The result is still above mozjemalloc, but
> the leak is plugged. Thanks.
> BTW, an interesting fact, if I didn't botch my stats: at the end of
> the 5 iterations, while 17MB are allocated, sucking 68MB of RSS, only
> 40MB worth of pages have allocated data in them. The number is similar
> to what I get with mozjemalloc (mozjemalloc is actually about 100K
> higher than jemalloc3 on that metric, while RSS is 6MB higher with
> jemalloc3) Which means (if my stats are not broken) that there is still
> room for improving RSS.
> Mike
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