Re: [PATCH] lazy freeing of memory through MADV_FREE

[Nick Piggin <nickpiggin@yahoo.com.au>]

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.

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