On Fri, Jan 29, 2016 at 05:43:28PM -0500, Rik van Riel wrote: > On 01/29/2016 05:23 PM, r...@redhat.com wrote: > > From: Rik van Riel <r...@redhat.com> > > > This speeds up > > ... ok, that changelog got truncated :( > > Here is the full version: > > > Because __acct_update_integrals does nothing unless the time > interval in question exceeds a jiffy, there is no real reason > to call it more than once a jiffy from the syscall, irq, and > guest entry & exit paths. > > If tasks get rescheduled frequently, the scheduler will still > update their time statistics normally. > > However, longer running tasks with frequent syscall, irq, > or guest entry & exit see a difference with this patch. > > A microbenchmark calling an invalid syscall number 10 million > times in a row speeds up an additional 30% over the numbers > with just the previous patch, for a total speedup of about 40% > over 4.4 and 4.5-rc1. > > Run times for the microbenchmark: > > 4.4 3.8 seconds > 4.5-rc1 3.7 seconds > 4.5-rc1 + first patch 3.3 seconds > 4.5-rc1 + both patches 2.3 seconds
Very nice improvement!
