On Tuesday 04 March 2008 06:02, Cyrus Massoumi wrote:Nick Piggin wrote:On Saturday 01 March 2008 01:54, Diego Calleja wrote:IIRC, going to fine-grained file locking gave them a huge boost in thisEl Fri, 29 Feb 2008 08:38:00 -0500, "Stephen Cuppett"escribió:
<cuppett@xxxxxxxxx>
There definitely were performance problems with threaded malloc/freeloads and 1500% at high loads. When compared with the best performingThere has been some performance problems with sysbench performance in
Linux kernel (2.6.22 or 2.6.24) performance is 15% better. Results are
linux which made it slower than freebsd, there were some patches to
speed things up, not sure if they have been merged.
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).
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.