FYI, we noticed a -98.8% improvement of xfstests.generic.027.seconds due to commit: commit dfd02e4de1c5f40c268984254045d388ab0c3e74 ("f2fs: fix to preallocate block only aligned to 4K") https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master in testcase: xfstests on test machine: qemu-system-x86_64 -enable-kvm -cpu qemu64,+ssse3 -smp 4 -m 4G with following parameters: disk: 4HDD fs: f2fs test: generic-slow2 xfstests is a regression test suite for xfs and other files ystems. Disclaimer: Results have been estimated based on internal Intel analysis and are provided for informational purposes only. Any difference in system hardware or software design or configuration may affect actual performance. Details are as below: --------------------------------------------------------------------------------------------------> To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp run job.yaml ========================================================================================= compiler/disk/fs/kconfig/rootfs/tbox_group/test/testcase: gcc-6/4HDD/f2fs/x86_64-rhel/debian-x86_64-2016-08-31.cgz/vm-kbuild-4G/generic-slow2/xfstests commit: 6a7a3aedd5 ("f2fs: fix non static symbol warning") dfd02e4de1 ("f2fs: fix to preallocate block only aligned to 4K") 6a7a3aedd562838f dfd02e4de1c5f40c2689842540 ---------------- -------------------------- fail:runs %reproduction fail:runs | | | %stddev %change %stddev \ | \ 2854 ± 1% -98.8% 35.00 ± 8% xfstests.generic.027.seconds 3103 ± 1% -90.9% 283.10 ± 1% xfstests.time.elapsed_time 3103 ± 1% -90.9% 283.10 ± 1% xfstests.time.elapsed_time.max 1323384 ± 0% -7.3% 1227062 ± 0% xfstests.time.file_system_inputs 72766 ± 1% -60.9% 28465 ± 6% xfstests.time.involuntary_context_switches 6753170 ± 0% +30.6% 8817851 ± 0% xfstests.time.minor_page_faults 5.00 ± 0% +760.0% 43.00 ± 4% xfstests.time.percent_of_cpu_this_job_got 158.03 ± 1% -40.1% 94.67 ± 5% xfstests.time.system_time 21.85 ± 2% +27.8% 27.92 ± 2% xfstests.time.user_time 226741 ± 0% -47.0% 120221 ± 1% xfstests.time.voluntary_context_switches xfstests.generic.027.seconds 3000 ++----------------------*-----------------------*--------------------+ *..*.*..*..*.*..*..*.*. * *.*..*. *..* | 2500 ++ : : | | : : | | : : | 2000 ++ : : | | : : | 1500 ++ : : | | *..*..*.* | 1000 ++ | | | | | 500 ++ | | | 0 O+-O-O--O--O-O--O--O-O--O--O-O--O--O-O--O-O--O--O-O--O--O-O--O--O-O--O xfstests.time.user_time 30 ++---------------------------------------------------------------------+ | | 28 O+ O O O O O O O O O | | O O O O O O O O O O O O O O O O O | | 26 ++ | | | 24 ++ | | *.. | 22 ++ * .*. .. | | .. : *..*. * *.* *..* | | .* : .. : .. | 20 *+.*.*..*. * : .* | | : .*.. .*. | 18 ++----------------------------*-----*----------------------------------+ xfstests.time.percent_of_cpu_this_job_got 50 ++---------------------------------------------------------------------+ | O | 45 O+ O O O O O O O O O O O 40 ++ O O O O O O O O O O O O | | O O | 35 ++ | 30 ++ | | | 25 ++ | 20 ++ | | | 15 ++ | 10 ++ | | .*..*..*.*.. | 5 *+-*-*--*--*--*-*--*--*--*-*-------------*--*-*--*--*--*---------------+ xfstests.time.minor_page_faults 9.5e+06 ++----------------------------------------------------------------+ | | 9e+06 O+ O O O O O O O O O O O O O O O O O O O O | O O O O O O | 8.5e+06 ++ | | | 8e+06 ++ | | | 7.5e+06 ++ | | | 7e+06 ++ .*. | *..*.*..*.*..*.*. *..*.* *..*.*..*.*..* | 6.5e+06 ++ + + | | + .*.. .* | 6e+06 ++--------------------------*----*--------------------------------+ xfstests.time.voluntary_context_switches 240000 ++-----------------------------------------------------------------+ *.. .*..*.*..*.*..*..*.*..* *.*..*.*..*..* | 220000 ++ * : : | | : : | 200000 ++ : : | | : : | 180000 ++ *..*..*.* | | | 160000 ++ | | | 140000 ++ | | | 120000 O+ O O O O O O O O O O O O O O O O O O O O O O O O O O | | 100000 ++-----------------------------------------------------------------+ xfstests.time.involuntary_context_switches 80000 ++------------------------------------------------------------------+ | .*.. .*. .*.. | 70000 *+.*.*..*.*..*..* *. * *..*.*. *.* | | : : | | : : | 60000 ++ : : | | *.*..*..* | 50000 ++ | | | 40000 ++ | | | | O O | 30000 O+ O O O O O O O O O O O O O O O O O | O O O O O O O | 20000 ++------------------------------------------------------------------+ xfstests.time.file_system_inputs 1.36e+06 ++---------------------------------------------------------------+ | *.*..*.* | 1.34e+06 ++ + + | | + + | 1.32e+06 *+.*.*..*.*..*.*..*.*..*.* *.*..*.*..*.* | | | 1.3e+06 ++ | | | 1.28e+06 ++ | | | 1.26e+06 ++ | | | 1.24e+06 ++ | O O O O O O O O O O O O O O O O O O O O O O O O O O O 1.22e+06 ++---------------------------------------------------------------+ [*] bisect-good sample [O] bisect-bad sample Thanks, Xiaolong