Messages in this thread | | | Date | Mon, 18 Oct 2021 14:43:55 +0200 | From | Borislav Petkov <> | Subject | Re: 回复:[PATCH] perf : optimiz e clear page in Intel specified model with movq instruction |
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On Mon, Oct 18, 2021 at 03:43:46PM +0800, JY Ni wrote: > _*Precondition:*__*do tests on a Intel CPX server.*_ CPU information of my > test machine is in backup part._*
My machine:
processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 106 stepping : 4
That's a SKYLAKE_X.
I ran
./tools/perf/perf stat --repeat 5 --sync --pre=/root/bin/pre-build-kernel.sh -- make -s -j96 bzImage
on -rc6, building allmodconfig each of the 10 times.
pre-build-kernel.sh is
--- #!/bin/bash
make -s clean echo 3 > /proc/sys/vm/drop_caches ---
Results are below but to me that's all "in the noise" with around one percent if I can trust the stddev. Which is not even close to 40%.
So basically you're wasting your time.
5.15-rc6 --------
# ./tools/perf/perf stat --repeat 5 --sync --pre=/root/bin/pre-build-kernel.sh -- make -s -j96 bzImage
Performance counter stats for 'make -s -j96 bzImage' (5 runs):
3,072,392.92 msec task-clock # 51.109 CPUs utilized ( +- 0.05% ) 1,351,534 context-switches # 440.257 /sec ( +- 0.99% ) 224,862 cpu-migrations # 73.248 /sec ( +- 1.39% ) 85,073,723 page-faults # 27.712 K/sec ( +- 0.01% ) 8,743,357,421,495 cycles # 2.848 GHz ( +- 0.06% ) 7,643,946,991,468 instructions # 0.88 insn per cycle ( +- 0.00% ) 1,705,128,638,240 branches # 555.440 M/sec ( +- 0.00% ) 37,637,576,027 branch-misses # 2.21% of all branches ( +- 0.03% ) 22,511,903,971,150 slots # 7.333 G/sec ( +- 0.03% ) 7,377,211,958,188 topdown-retiring # 32.5% retiring ( +- 0.02% ) 3,145,247,374,138 topdown-bad-spec # 13.9% bad speculation ( +- 0.27% ) 8,018,664,899,041 topdown-fe-bound # 35.2% frontend bound ( +- 0.07% ) 4,167,103,609,622 topdown-be-bound # 18.3% backend bound ( +- 0.09% )
60.114 +- 0.112 seconds time elapsed ( +- 0.19% )
5.15-rc6 + patch ----------------
Performance counter stats for 'make -s -j96 bzImage' (5 runs):
3,033,250.65 msec task-clock # 51.243 CPUs utilized ( +- 0.05% ) 1,329,033 context-switches # 438.210 /sec ( +- 0.64% ) 225,550 cpu-migrations # 74.369 /sec ( +- 1.36% ) 85,080,938 page-faults # 28.053 K/sec ( +- 0.00% ) 8,629,663,367,477 cycles # 2.845 GHz ( +- 0.05% ) 7,696,237,813,803 instructions # 0.89 insn per cycle ( +- 0.00% ) 1,709,909,494,107 branches # 563.793 M/sec ( +- 0.00% ) 37,719,552,337 branch-misses # 2.21% of all branches ( +- 0.02% ) 22,214,249,023,820 slots # 7.325 G/sec ( +- 0.06% ) 7,412,342,725,008 topdown-retiring # 33.0% retiring ( +- 0.01% ) 3,141,090,408,028 topdown-bad-spec # 14.1% bad speculation ( +- 0.17% ) 7,996,077,873,517 topdown-fe-bound # 35.6% frontend bound ( +- 0.03% ) 3,862,154,886,962 topdown-be-bound # 17.3% backend bound ( +- 0.28% )
59.193 +- 0.302 seconds time elapsed ( +- 0.51% )
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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