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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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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