lkml.org 
[lkml]   [2015]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH 0/3] reduce nohz_full syscall overhead by 10%
Date
Profiling reveals that a lot of the overhead from the nohz_full
accounting seems to come not from the accounting itself, but from
disabling and re-enabling interrupts.

This patch series removes the interrupt disabling & re-enabling
from __acct_update_integrals, which is called on both syscall
entry and exit, as well as from the user_exit called on syscall
entry.

Together they speed up a benchmark that calls getpriority in
a row 10 million times by about 10%:

run time system time
vanilla 5.49s 2.08s
__acct patch 5.21s 1.92s
both patches 4.88s 1.71s



\
 
 \ /
  Last update: 2015-05-01 00:01    [W:0.140 / U:2.848 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site