Re: [PATCH 0/4 v6] sched,time: reduce nohz_full syscall overhead 40%

2016-02-24 Thread Thomas Gleixner
On Wed, 10 Feb 2016, r...@redhat.com wrote: > (v6: make VIRT_CPU_ACCOUNTING_GEN jiffy granularity) > > Running with nohz_full introduces a fair amount of overhead. > Specifically, various things that are usually done from the > timer interrupt are now done at syscall, irq, and guest > entry and e

Re: [PATCH 0/4 v6] sched,time: reduce nohz_full syscall overhead 40%

2016-02-15 Thread Mike Galbraith
Hi Rik, On Wed, 2016-02-10 at 20:08 -0500, r...@redhat.com wrote: > I tested this series with a microbenchmark calling > an invalid syscall number ten million times in a row, > on a nohz_full cpu. > > Run times for the microbenchmark: > > 4.4 3.8 seconds > 4.

[PATCH 0/4 v6] sched,time: reduce nohz_full syscall overhead 40%

2016-02-10 Thread riel
(v6: make VIRT_CPU_ACCOUNTING_GEN jiffy granularity) Running with nohz_full introduces a fair amount of overhead. Specifically, various things that are usually done from the timer interrupt are now done at syscall, irq, and guest entry and exit times. However, some of the code that is called ever