Re: Performance versus FreeBSD 7.0

[Cyrus Massoumi <cyrusm@gmx.net>]

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

> But it was very nice to be made aware of the problem and be able to
> improve it.
> 
> 
>> Myself I find fun that they look at Linux as the Leader That Must Be
>> Surpassed. All the performance highlights of freebsd 7.0 are things that
>> linux already did some years ago.
> 
> I don't know very much about FreeBSD nor have verified the results
> for myself. But to their credit they seem to have done quite well at
> least on the smaller end of the scale.