Re: SMP performance degradation with sysbench

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From: Nick Piggin
Date: Tuesday, March 13, 2007 - 4:56 am

Eric Dumazet wrote:

Well that doesn't help in this case. I tested and the mmap_sem contention
is not an issue.


The idea is a good one, and I was half way through implementing similar
myself at one point (some java apps hit this badly).

It is just horribly sad that futexes are supposed to implement a
_scalable_ thread synchronisation mechanism, whilst fundamentally
relying on an mm-wide lock to operate.

I don't like your interface, but then again, the futex interface isn't
exactly pretty anyway.

You should resubmit the patch, and get the glibc guys to use it.

-- 
SUSE Labs, Novell Inc.
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Messages in current thread:
SMP performance degradation with sysbench, Lorenzo Allegrucci, (Sun Feb 25, 10:44 am)
Re: SMP performance degradation with sysbench, Rik van Riel, (Sun Feb 25, 4:46 pm)
Re: SMP performance degradation with sysbench, Nick Piggin, (Mon Feb 26, 6:36 am)
Re: SMP performance degradation with sysbench, Nick Piggin, (Mon Feb 26, 6:41 am)
Re: SMP performance degradation with sysbench, Pete Harlan, (Mon Feb 26, 3:04 pm)
Re: SMP performance degradation with sysbench, Dave Jones, (Mon Feb 26, 3:36 pm)
Re: SMP performance degradation with sysbench, Hiro Yoshioka, (Mon Feb 26, 5:32 pm)
Re: SMP performance degradation with sysbench, Rik van Riel, (Mon Feb 26, 5:43 pm)
Re: SMP performance degradation with sysbench, Hiro Yoshioka, (Mon Feb 26, 9:03 pm)
Re: SMP performance degradation with sysbench, Rik van Riel, (Mon Feb 26, 9:31 pm)
Re: SMP performance degradation with sysbench, J.A. , (Tue Feb 27, 1:14 am)
Re: SMP performance degradation with sysbench, Rik van Riel, (Tue Feb 27, 7:02 am)
Re: SMP performance degradation with sysbench, Paulo Marques, (Tue Feb 27, 7:56 am)
Re: SMP performance degradation with sysbench, Lorenzo Allegrucci, (Tue Feb 27, 12:05 pm)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Tue Feb 27, 1:40 pm)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Tue Feb 27, 6:27 pm)
Re: SMP performance degradation with sysbench, Bill Davidsen, (Tue Feb 27, 7:21 pm)
Re: SMP performance degradation with sysbench, Nick Piggin, (Tue Feb 27, 7:22 pm)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Tue Feb 27, 7:51 pm)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Tue Feb 27, 7:52 pm)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Wed Feb 28, 5:20 pm)
Re: SMP performance degradation with sysbench, Lorenzo Allegrucci, (Thu Mar 1, 9:57 am)
Re: SMP performance degradation with sysbench, Anton Blanchard, (Mon Mar 12, 3:00 pm)
Re: SMP performance degradation with sysbench, Nick Piggin, (Mon Mar 12, 10:11 pm)
Re: SMP performance degradation with sysbench, Eric Dumazet, (Mon Mar 12, 11:00 pm)
Re: SMP performance degradation with sysbench, Andrea Arcangeli, (Tue Mar 13, 2:45 am)
Re: SMP performance degradation with sysbench, Nick Piggin, (Tue Mar 13, 3:06 am)
Re: SMP performance degradation with sysbench, Andrea Arcangeli, (Tue Mar 13, 3:31 am)
Re: SMP performance degradation with sysbench, Nick Piggin, (Tue Mar 13, 3:37 am)
Re: SMP performance degradation with sysbench, Andrea Arcangeli, (Tue Mar 13, 3:57 am)
Re: SMP performance degradation with sysbench, Nick Piggin, (Tue Mar 13, 4:12 am)
Re: SMP performance degradation with sysbench, Eric Dumazet, (Tue Mar 13, 4:40 am)
Re: SMP performance degradation with sysbench, Andrea Arcangeli, (Tue Mar 13, 4:42 am)
Re: SMP performance degradation with sysbench, Nick Piggin, (Tue Mar 13, 4:56 am)
Re: SMP performance degradation with sysbench, Eric Dumazet, (Tue Mar 13, 5:02 am)
Re: SMP performance degradation with sysbench, Nick Piggin, (Tue Mar 13, 5:08 am)
Re: SMP performance degradation with sysbench, Jakub Jelinek, (Tue Mar 13, 5:27 am)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Tue Mar 13, 5:36 pm)
Re: SMP performance degradation with sysbench, Eric Dumazet, (Tue Mar 13, 6:00 pm)
Re: SMP performance degradation with sysbench, Nish Aravamudan, (Tue Mar 13, 6:09 pm)
Re: SMP performance degradation with sysbench, Siddha, Suresh B, (Wed Mar 14, 4:33 pm)
Re: SMP performance degradation with sysbench, Zhang, Yanmin, (Mon Mar 19, 7:29 pm)
Re: SMP performance degradation with sysbench, Zhang, Yanmin, (Sun Apr 1, 7:59 pm)