Chris Mason wrote on Thursday, June 01, 2006 3:56 PM
> Hello everyone,
>
> Recent benchmarks showed some performance regressions between 2.6.16 and
> 2.6.5. We tracked down one of the regressions to lock contention in schedule
> heavy workloads (~70,000 context switches per second)
>
> kernel/sched.c:dependent_sleeper() was responsible for most of the lock
> contention, hammering on the run queue locks. The patch below is more of
> a discussion point than a suggested fix (although it does reduce lock
> contention significantly). The dependent_sleeper code looks very expensive
> to me, especially for using a spinlock to bounce control between two different
> siblings in the same cpu.
Yeah, this also sort of echo a recent discovery on one of our benchmarks
that schedule() is red hot in the kernel. I was just scratching my head
not sure what's going on. This dependent_sleeper could be the culprit
considering it is called almost at every context switch. I don't think
we are hitting on lock contention, but by the large amount of code it
executes. It really needs to be cut down ....
- Ken
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
