On Wed, Feb 01, 2017 at 11:41:50PM +0100, Borislav Petkov wrote:
> More playing with this tomorrow. It is late here and brain wants to
> sleep now.
Ok, did some measurements of our favourite workload with and without
those patches on rc6+tip/master.
It is a Kaveri laptop so small, only 2 CUs. perf command was:
./tools/perf/perf stat -e
task-clock,context-switches,cache-misses,cpu-migrations,page-faults,cycles,instructions,branches,branch-misses
--repeat 3 --sync --pre /path/to/pre-build-kernel.sh -- make -s -j5 bzImage
and that script is:
$ cat pre-build-kernel.sh
#!/bin/bash
make -s clean
echo 3 > /proc/sys/vm/drop_caches
Here the results:
before:
Performance counter stats for 'make -s -j5 bzImage' (3 runs):
1457712.248049 task-clock (msec) # 3.612 CPUs utilized
( +- 1.20% )
400,872 context-switches # 0.275 K/sec
( +- 0.23% )
8,675,334,184 cache-misses
( +- 0.15% )
26,915 cpu-migrations # 0.018 K/sec
( +- 2.13% )
23,806,184 page-faults # 0.016 M/sec
( +- 0.00% )
3,648,915,008,651 cycles # 2.503 GHz
( +- 0.91% )
1,895,555,704,111 instructions # 0.52 insn per cycle
( +- 0.00% )
426,444,023,897 branches # 292.543 M/sec
( +- 0.00% )
26,127,609,710 branch-misses # 6.13% of all branches
( +- 0.02% )
403.601384883 seconds time elapsed
( +- 1.18% )
after:
Performance counter stats for 'make -s -j5 bzImage' (3 runs):
1436580.109340 task-clock (msec) # 3.614 CPUs utilized
( +- 1.37% )
396,949 context-switches # 0.276 K/sec
( +- 0.08% )
8,655,078,022 cache-misses
( +- 0.36% )
30,623 cpu-migrations # 0.021 K/sec
( +- 0.46% )
23,788,698 page-faults # 0.017 M/sec
( +- 0.00% )
3,568,254,088,919 cycles # 2.484 GHz
( +- 0.88% )
1,895,348,016,179 instructions # 0.53 insn per cycle
( +- 0.00% )
426,405,814,017 branches # 296.820 M/sec
( +- 0.00% )
26,090,473,525 branch-misses # 6.12% of all branches
( +- 0.04% )
397.531904252 seconds time elapsed
( +- 1.20% )
Context switches have dropped, cache misses are the same and we have a
rise in cpu-migrations. That last bit is interesting and I don't have an
answer yet. Maybe peterz has an idea.
Cycles have dropped too.
And we're 6 secs faster so I'll take that.
Now on to run the same thing on a bigger bulldozer.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
