Re: [PATCH] lazy freeing of memory through MADV_FREE

Nick Piggin
2007-04-23T04:36:27Z

Jakub Jelinek wrote:
> On Fri, Apr 20, 2007 at 07:52:44PM -0400, Rik van Riel wrote:
>
>>It turns out that Nick's patch does not improve peak
>>performance much, but it does prevent the decline when
>>running with 16 threads on my quad core CPU!
>>
>>We _definately_ want both patches, there's a huge benefit
>>in having them both.
>>
>>Here are the transactions/seconds for each combination:
>>
>> vanilla new glibc madv_free kernel madv_free + mmap_sem
>>threads
>>
>>1 610 609 596 545
>>2 1032 1136 1196 1200
>>4 1070 1128 2014 2024
>>8 1000 1088 1665 2087
>>16 779 1073 1310 1999
>
>
> FYI, I have uploaded a testing glibc that uses MADV_FREE and falls back
> to MADV_DONTUSE if MADV_FREE is not available, to
> http://people.redhat.com/jakub/glibc/2.5.90-21.1/

Hmm, I wonder how glibc malloc stacks up to tcmalloc on this test
(after the mmap_sem patch as well).

I'll try running that as well!

--
SUSE Labs, Novell Inc.