Messages in this thread |  | | Subject | Re: [PATCH v2] sched, timer: Use atomics for thread_group_cputimer to improve scalability | From | Jason Low <> | Date | Thu, 19 Mar 2015 13:14:14 -0700 |
| |
On Thu, 2015-03-19 at 10:59 -0700, Linus Torvalds wrote: > On Thu, Mar 19, 2015 at 10:21 AM, Jason Low <jason.low2@hp.com> wrote: > > > > I tested this patch on a 32 bit ARM system with 4 cores. Using the > > generic 64 bit atomics, I did not see any performance change with this > > patch, and the relevant functions (account_group_*_time(), ect...) don't > > show up in perf reports. > > Ok. > > > One factor might be because locking/cacheline contention isn't as > > apparent on smaller systems to begin with, and lib/atomic64.c also > > mentions that "this is expected to used on systems with small numbers of > > CPUs (<= 4 or so)". > > Yeah, that's probably a valid argument anyway - 32-bit systems aren't > really going to be multi-node big systems any more. > > So I'm ok with the patch,
Okay, I will be sending out a v3 patch which will also mention a bit about its effect on 32 bit systems in the changelog, in addition to the changes that were discussed about in this thread (using WRITE_ONCE(), ect...).
Thanks, Jason
|  |