Memory usage regression
mh+jemalloc at glandium.org
Wed Oct 24 14:22:07 PDT 2012
On Wed, Oct 24, 2012 at 09:36:54PM +0200, Mike Hommey wrote:
> With that replayed workload, I can see two main things:
> - The amount of resident memory used by jemalloc 3 is greater than that
> of mozjemalloc after freeing big parts of what was allocated (in
> Firefox, after closing all tabs, waiting for a settle, and forcing GC).
> This is most likely due to different allocation patterns leading to
> some kind of fragmentation after freeing part of the allocated memory.
> See http://i.imgur.com/fQKi4.png for a graphical representation of
> what happens to the RSS value at the different checkpoints during the
> Firefox workload.
> - The amount of mmap()ed memory is dangerously increasing during the
> workload. It almost (but not quite) looks like jemalloc don't reuse
> pages it purged. See http://i.imgur.com/klfJv.png ; VmData is
> essentially the sum of all anonymous ranges of memory in the process.
> Such an increase in VmData means we'd eventually exhaust the 32-bits
> address space on 32-bits OSes, even though the resident memory usage
> is pretty low.
FWIW, both jemalloc 2.0.0 and 1.0.3 have the same behaviour as jemalloc
3, both for VmRSS and VmData.
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