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From: Cyrus Massoumi <cyrusm@gmx.net>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Diego Calleja <diegocg@gmail.com>,
	Stephen Cuppett <cuppett@gmail.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu,
	a.p.zijlstra@chello.nl
Subject: Re: Performance versus FreeBSD 7.0
Date: Mon, 03 Mar 2008 23:47:06 +0100	[thread overview]
Message-ID: <47CC7FEA.5050508@gmx.net> (raw)
In-Reply-To: <200803040624.24119.nickpiggin@yahoo.com.au>

Nick Piggin wrote:
> On Tuesday 04 March 2008 06:02, Cyrus Massoumi wrote:
>> Nick Piggin wrote:
>>> On Saturday 01 March 2008 01:54, Diego Calleja wrote:
>>>> El Fri, 29 Feb 2008 08:38:00 -0500, "Stephen Cuppett"
>>>> <cuppett@gmail.com>
>>> escribió:
>>>>> loads and 1500% at high loads. When compared with the best performing
>>>>> Linux kernel (2.6.22 or 2.6.24) performance is 15% better. Results are
>>>> There has been some performance problems with sysbench performance in
>>>> linux which made it slower than freebsd, there were some patches to
>>>> speed things up, not sure if they have been merged.
>>> There definitely were performance problems with threaded malloc/free
>>> in the Linux kernel and glibc. Fixes have been merged in both packages,
>>> and AFAIK the FreeBSD guys tested with those fixes in place.
>>>
>>> I think these were never really run into before in part due to MySQL's
>>> unscalable heap design makes it not scale well on higher numbers of
>>> CPUs anyway, and also made the malloc problems more pronounced (ie.
>>> they added a bit to the contention of the single heap lock, which is
>>> the big killer here).
>> IIRC, going to fine-grained file locking gave them a huge boost in this
>> particular benchmark (and maybe others).
>> As I said on lwn.net Peter Zijlstra posted a patch to break the global
>> file list lock about a year ago [1], but I don't think it was ever
>> merged. Here [2] are some numbers for the patchset.
>>
>> [1] http://lkml.org/lkml/2007/1/28/29
>> [2] http://lkml.org/lkml/2007/1/28/116
> 
> The mysql workload is not constrained by this lock. The important
> part (where freebsd saw their gain) is probably fd lookups, which
> are lockless in Linux for a long time.

Thanks for pointing this out Nick.


  reply	other threads:[~2008-03-03 22:46 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-29 13:38 Stephen Cuppett
2008-02-29 14:54 ` Diego Calleja
2008-03-03 13:04   ` Nick Piggin
2008-03-03 19:02     ` Cyrus Massoumi
2008-03-03 19:24       ` Nick Piggin
2008-03-03 22:47         ` Cyrus Massoumi [this message]
2008-03-03 23:23       ` Andi Kleen
2008-03-04  5:51         ` Cyrus Massoumi
2008-03-06 12:53         ` Nick Piggin
2008-03-06 13:12           ` Andi Kleen
2008-03-03 12:34 ` Andi Kleen
2008-03-06 17:29 ` debian developer
2008-03-06 17:34   ` debian developer
     [not found] <a2dDb-60y-29@gated-at.bofh.it>
     [not found] ` <a2eSt-7UK-1@gated-at.bofh.it>
2009-01-25 10:07   ` Lx

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