On 5/26/2021 12:44 AM, Bart Van Assche wrote:
On 5/24/21 11:44 PM, kernel test robot wrote:FYI, we noticed a 12.8% improvement of netperf.Throughput_tps due to commit: commit: 2463a604a86728777ce4284214a52de46a808c9e ("[PATCH v3 2/3] Introduce enums for the SAM, message, host and driver status codes") url: https://github.com/0day-ci/linux/commits/Bart-Van-Assche/Introduce-enums-for-SCSI-status-codes/20210524-105751 base: https://git.kernel.org/cgit/linux/kernel/git/mkp/scsi.git for-next in testcase: netperf on test machine: 192 threads 4 sockets Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz with 192G memory with following parameters: ip: ipv4 runtime: 300s nr_threads: 16 cluster: cs-localhost test: TCP_CRR cpufreq_governor: performance ucode: 0x5003006 test-description: Netperf is a benchmark that can be use to measure various aspect of networking performance. test-url: http://www.netperf.org/netperf/The above email reports a performance improvement for the networking subsystem while my patch only affects the SCSI subsystem and should not have any performance impact. I'm confused by the above feedback ...
I suspect it related with cache alignment, 2463a604a8 changes "u8" (size:1) to "enum xxx_status" (size: 4), the cache alignment is better than before , so cause the improvement.
Bart. _______________________________________________ LKP mailing list -- lkp@xxxxxxxxxxxx To unsubscribe send an email to lkp-leave@xxxxxxxxxxxx
-- Zhengjun Xing
