[linus:master] [jbd2] 6a3afb6ac6: fileio.latency_95th_ms 92.5% regression

From: kernel test robot
Date: Tue Jan 02 2024 - 02:31:45 EST




Hello,

kernel test robot noticed a 92.5% regression of fileio.latency_95th_ms on:


commit: 6a3afb6ac6dfab158ebdd4b87941178f58c8939f ("jbd2: increase the journal IO's priority")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

testcase: fileio
test machine: 128 threads 2 sockets Intel(R) Xeon(R) Platinum 8358 CPU @ 2.60GHz (Ice Lake) with 128G memory
parameters:

period: 600s
nr_threads: 100%
disk: 1HDD
fs: ext4
size: 64G
filenum: 1024f
rwmode: seqwr
iomode: sync
cpufreq_governor: performance




If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-lkp/202401021525.a27b9444-oliver.sang@xxxxxxxxx


Details are as below:
-------------------------------------------------------------------------------------------------->


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20240102/202401021525.a27b9444-oliver.sang@xxxxxxxxx

=========================================================================================
compiler/cpufreq_governor/disk/filenum/fs/iomode/kconfig/nr_threads/period/rootfs/rwmode/size/tbox_group/testcase:
gcc-12/performance/1HDD/1024f/ext4/sync/x86_64-rhel-8.3/100%/600s/debian-11.1-x86_64-20220510.cgz/seqwr/64G/lkp-icl-2sp5/fileio

commit:
8555922721 ("jbd2: correct the printing of write_flags in jbd2_write_superblock()")
6a3afb6ac6 ("jbd2: increase the journal IO's priority")

85559227211020b2 6a3afb6ac6dfab158ebdd4b8794
---------------- ---------------------------
%stddev %change %stddev
\ | \
37.99 ± 9% +92.5% 73.13 fileio.latency_95th_ms
19872 ± 16% -24.1% 15078 ± 21% numa-meminfo.node1.Active(file)
24.74 ± 6% +97.3% 48.81 ± 2% perf-sched.wait_time.avg.ms.kjournald2.kthread.ret_from_fork.ret_from_fork_asm
8157448 -5.7% 7691858 ± 2% proc-vmstat.pgpgout
13464 -5.7% 12700 ± 2% vmstat.io.bo
4968 ± 16% -24.1% 3768 ± 21% numa-vmstat.node1.nr_active_file
4968 ± 16% -24.1% 3768 ± 21% numa-vmstat.node1.nr_zone_active_file
1413 +2.8% 1452 ± 2% perf-stat.i.cycles-between-cache-misses
1.59 -2.9% 1.54 perf-stat.overall.MPKI
1368 +2.5% 1402 perf-stat.overall.cycles-between-cache-misses
161.13 ± 9% +17.4% 189.23 ± 10% sched_debug.cpu.curr->pid.avg
25531 ± 6% -12.4% 22376 ± 8% sched_debug.cpu.nr_switches.stddev
-93.66 +38.8% -130.00 sched_debug.cpu.nr_uninterruptible.min




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.


--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki