[lkml]   [2007]   [Mar]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: SMP performance degradation with sysbench
Anton Blanchard a écrit :
> Hi Nick,
>> Anyway, I'll keep experimenting. If anyone from MySQL wants to help look
>> at this, send me a mail (eg. especially with the sched_setscheduler issue,
>> you might be able to do something better).
> I took a look at this today and figured Id document it:
> Bottom line: it looks like issues in the glibc malloc library, replacing
> it with the google malloc library fixes the negative scaling:
> # apt-get install libgoogle-perftools0
> # LD_PRELOAD=/usr/lib/ /usr/sbin/mysqld

Hi Anton, thanks for the report.
glibc has certainly many scalability problems.

One of the known problem is its (ab)use of mmap() to allocate one (yes : one
!) page every time you fopen() a file. And then a munmap() at fclose() time.

mmap()/munmap() should be avoided as hell in multithreaded programs.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-03-13 07:03    [W:0.147 / U:9.280 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site