On 26 June 2014 07:16, Fengguang Wu <fengguang.wu(a)intel.com> wrote:
I'm not sure how the simple commit will impact will-it-scale/pwrite2
throughput. Just in case you can see more clues.
commit d5a085970b0b88b8c82303d2c45f09c9427fd02a ("clockevents: x86: add support for
test case: nhm4/will-it-scale/pwrite2
773859 ~ 0% -9.2% 702704 ~ 0% TOTAL will-it-scale.per_thread_ops
~XX% - stddev percent
[+-]XX% - change percent
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.
Thanks for your link: https://github.com/antonblanchard/will-it-scale.git
You saw these changes because the simple commit you were talking about
changes behavior of code.
To be specific, we are stopping the clock-event devices now when they
aren't used. i.e. during idle periods or in full dynticks.
I still fail to understand why performance came down by 9.2%..
Adding Frederic in CC, in case he can throw some light. But he is currently
on vacations and I don't expect him to reply immediately :)