Re: [PATCH 00 of 66] Transparent Hugepage Support #32

From: CAI Qian
Date: Thu Nov 04 2010 - 04:42:45 EST


Thank Andrea for pointing out to me there are ongoing works for KSM and THP integration. Sorry for the noise.

CAI Qian

----- caiqian@xxxxxxxxxx wrote:

> There were some changes of behaviours with THP and KSM statistics
> demonstrated by this program, http://people.redhat.com/qcai/ksm01.c.
>
> There are 3 programs (A, B ,C) to allocate 128M memory each using KSM.
> A has memory content = 'c'.
> B has memory content = 'a'.
> C has memory content = 'a'.
> Then without THP,
> pages_shared = 2
> pages_sharing = 98285
> pages_sharing = 98292
> pages_unshared = 0
> pages_volatile = 17
> pages_to_scan = 98304
> sleep_millisecs = 0
> with THP,
> pages_shared is 2.
> pages_sharing is 18422.
> pages_unshared is 0.
> pages_volatile is 8.
>
> Later,
> A has memory content = 'c'
> B has memory content = 'b'
> C has memory content = 'a'.
> Then without THP,
> pages_shared = 3
> pages_sharing = 98296
> pages_unshared = 0
> pages_volatile = 5
> with THP,
> pages_shared = 3
> pages_sharing = 16358
> pages_unshared = 0
> pages_volatile = 23
>
> Later,
> A has memory content = 'd'
> B has memory content = 'd'
> C has memory content = 'd'
> Then without THP,
> pages_shared = 1
> pages_sharing = 98274
> pages_unshared = 0
> pages_volatile = 29
> with THP,
> pages_shared = 1
> pages_sharing = 8668
> pages_unshared = 0
> pages_volatile = 35
>
> Finally,
> A changes one page to 'e'
> Then without THP,
> pages_shared = 1
> pages_sharing = 98274
> pages_unshared = 1
> pages_volatile = 28
> with THP,
> pages_shared = 1
> pages_sharing = 8163
> pages_unshared = 1
> pages_volatile = 27
>
> Are those differences for pages_sharing between with and without THP
> are expected?
>
> CAI Qian
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