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Re: [PATCH] lazy freeing of memory through MADV_FREE

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From: Rik van Riel
Subject: Re: [PATCH] lazy freeing of memory through MADV_FREE
Date: Sunday, April 22, 2007 - 8:53 pm

Nick Piggin wrote:

I've added a 5th column, with just your mmap_sem patch and
without my madv_free patch.  It is run with the glibc patch,
which should make it fall back to MADV_DONTNEED after the
first MADV_FREE call fails.


Not doing the mprotect calls is the big one I guess, especially
the fact that we don't need to take the mmap_sem for writing.

With both our patches, single and two thread performance with
MySQL sysbench is somewhat better than with just your patch,
4 and 8 thread performance are basically the same and just
your patch gives a slight benefit with 16 threads.

I guess I should benchmark up to 64 or 128 threads tomorrow,
to see if this is just luck or if the cache benefit of doing
the page faults and reusing hot pages is faster than not
having page faults at all.

I should run some benchmarks on other systems, too.  Some of
these results could be an artifact of my quad core CPU.  The
results could be very different on other systems...


Maybe MySQL has various different threads to do
different tasks.  Something to look into...
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Messages in current thread:
[PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Tue Apr 17, 12:15 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE 2/2, Rik van Riel, (Thu Apr 19, 2:15 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Andrew Morton, (Fri Apr 20, 1:57 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE 2/2, Andrew Morton, (Fri Apr 20, 2:03 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE 2/2, Ulrich Drepper, (Fri Apr 20, 2:24 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Fri Apr 20, 2:38 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Andrew Morton, (Fri Apr 20, 3:06 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Fri Apr 20, 4:52 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Eric Dumazet, (Fri Apr 20, 5:48 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Fri Apr 20, 8:58 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Jakub Jelinek, (Sat Apr 21, 12:12 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Hugh Dickins, (Sat Apr 21, 12:24 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE 2/2, Hugh Dickins, (Sat Apr 21, 12:37 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE 2/2, Ulrich Drepper, (Sat Apr 21, 9:32 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Sat Apr 21, 11:06 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Sat Apr 21, 7:36 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Sat Apr 21, 7:50 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Sat Apr 21, 11:31 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Andrew Morton, (Sun Apr 22, 1:18 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Christoph Hellwig, (Sun Apr 22, 2:16 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Ulrich Drepper, (Sun Apr 22, 9:55 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Sun Apr 22, 5:16 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Sun Apr 22, 8:53 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Sun Apr 22, 8:58 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Sun Apr 22, 8:59 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Sun Apr 22, 9:28 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Sun Apr 22, 9:36 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 2:20 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Mon Apr 23, 3:07 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 3:12 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Mon Apr 23, 3:21 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 3:31 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Mon Apr 23, 3:35 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Jakub Jelinek, (Mon Apr 23, 3:44 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 3:44 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 4:45 am)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Mon Apr 23, 6:15 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 6:58 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Nick Piggin, (Mon Apr 23, 7:16 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 7:53 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Andrew Morton, (Mon Apr 23, 8:08 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Paul Mackerras, (Mon Apr 23, 9:42 pm)
Re: [PATCH] lazy freeing of memory through MADV_FREE, Rik van Riel, (Mon Apr 23, 10:13 pm)