[linus:master] [ext4] 7f373083b4: fio.write_iops 54.8% improvement

[linus:master] [ext4] 7f373083b4: fio.write_iops 54.8% improvement

[kernel test robot]

Hello,

kernel test robot noticed a 54.8% improvement of fio.write_iops on:


commit: 7f373083b45757b19f36a939f255239d40ccfb24 ("ext4: avoid unnecessary transaction in ext4_map_blocks() for unwritten extents") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

testcase: fio-basic
config: x86_64-rhel-9.4
compiler: gcc-14
test machine: 64 threads 2 sockets Intel(R) Xeon(R) Gold 6346 CPU @ 3.10GHz (Ice Lake) with 256G memory
parameters:

	runtime: 300s
	disk: 1HDD
	fs: ext4
	nr_task: 1
	test_size: 128G
	rw: write
	bs: 4k
	ioengine: falloc
	cpufreq_governor: performance


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


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20261108/202611080817.b5c132ae-lkp@intel.com

=========================================================================================
bs/compiler/cpufreq_governor/disk/fs/ioengine/kconfig/nr_task/rootfs/runtime/rw/tbox_group/test_size/testcase:
  4k/gcc-14/performance/1HDD/ext4/falloc/x86_64-rhel-9.4/1/debian-13-x86_64-20250902.cgz/300s/write/lkp-icl-2sp9/128G/fio-basic

commit: 
  6585cea3cf ("ext4: allow ext4_map_blocks() to start its own transaction handle")
  7f373083b4 ("ext4: avoid unnecessary transaction in ext4_map_blocks() for unwritten extents")

6585cea3cf58b8e8 7f373083b45757b19f36a939f25
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
      0.08 ±  5%      -0.1        0.02 ±  4%  fio.latency_2us%
      0.05 ±  2%      -0.0        0.02 ±  5%  fio.latency_4us%
     27.91           -34.9%      18.16        fio.time.elapsed_time
     27.91           -34.9%      18.16        fio.time.elapsed_time.max
     17.90           -46.7%       9.54        fio.time.system_time
      3013           -34.2%       1984        fio.time.voluntary_context_switches
      4758           +54.8%       7366        fio.write_bw_MBps
    648.00           -44.7%     358.67        fio.write_clat_90%_ns
    652.00           -44.4%     362.67        fio.write_clat_95%_ns
    664.00           -43.9%     372.67        fio.write_clat_99%_ns
    632.44           -43.9%     354.58        fio.write_clat_mean_ns
   1218093           +54.8%    1885792        fio.write_iops


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