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 -- All rights reversed
