[linus:master] [fs/pipe] f7f4665dc5: lmbench3.PIPE.bandwidth.MB/sec 18.5% regression

[kernel test robot <yi1.lai@intel.com>]

Hello,

kernel test robot noticed a 18.5% regression of lmbench3.PIPE.bandwidth.MB/sec on:


commit: f7f4665dc520fd8bbc1db20e59945773e03744a0 ("fs/pipe: unify the page pools into a single per-pipe pool") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

testcase: lmbench3
config: x86_64-rhel-9.4
compiler: gcc-14
test machine: 224 threads 2 sockets Intel(R) Xeon(R) (Sapphire Rapids) with 128G memory
parameters:

	test_memory_size: 50%
	nr_threads: 20%
	mode: development
	test: PIPE
	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 <yi1.lai@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202611041404.befe64cd-lkp@intel.com

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

The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20261104/202611041404.befe64cd-lkp@intel.com

=========================================================================================
compiler/cpufreq_governor/kconfig/mode/nr_threads/rootfs/tbox_group/test/test_memory_size/testcase:
  gcc-14/performance/x86_64-rhel-9.4/development/20%/debian-13-x86_64-20250902.cgz/lkp-spr-2sp2/PIPE/50%/lmbench3

commit: 
  c610d2d078 ("fs: annotate inode timestamp accessors")
  f7f4665dc5 ("fs/pipe: unify the page pools into a single per-pipe pool")

c610d2d0787961cd f7f4665dc520fd8bbc1db20e599
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
     29142 ±  2%     -18.5%      23737        lmbench3.PIPE.bandwidth.MB/sec
    191.80 ±  8%     +54.1%     295.65 ±  5%  lmbench3.time.elapsed_time
    191.80 ±  8%     +54.1%     295.65 ±  5%  lmbench3.time.elapsed_time.max
     23261 ± 16%     +19.3%      27743 ±  5%  lmbench3.time.involuntary_context_switches
      9853 ± 16%     +27.9%      12605 ±  5%  lmbench3.time.system_time
     51.80 ±  2%     +11.6%      57.80 ±  3%  lmbench3.time.user_time
 2.928e+08 ±  3%     +26.6%  3.706e+08 ±  4%  lmbench3.time.voluntary_context_switches


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