* Rob Hussey <[email protected]> wrote:
> The obligatory graphs:
> http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_lat_ctx_benchmark.png
> http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_hackbench_benchmark.png
> http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_pipe-test_benchmark.png
btw., it's likely that if you turn off CONFIG_PREEMPT for .21 and for
.22-ck1 they'll improve a bit too - so it's not fair to put the .23
!PREEMPT numbers on the graph as the PREEMPT numbers of the other
kernels. (it shows the .23 scheduler being faster than it really is)
> A cursory glance suggests that performance wrt lat_ctx and hackbench
> has increased (lower numbers), but degraded quite a lot for pipe-test.
> The numbers for pipe-test are extremely stable though, while the
> numbers for hackbench are more erratic (which isn't saying much since
> the original numbers gave nearly a straight line). I'm still willing
> to try out any more ideas.
the pipe-test behavior looks like an outlier. !PREEMPT only removes code
(which makes the code faster), so this could be a cache layout artifact.
(or perhaps we preempt at a different point which is disadvantageous to
caching?) Pipe-test is equivalent to "lat_ctx -s 0 2" so if there was a
genuine slowdown it would show up in the lat_ctx graph - but the graph
shows a speedup.
Ingo
-
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]
