Messages in this thread | | | Date | Wed, 22 Apr 2015 17:29:40 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/2] timer: Avoid waking up an idle-core by migrate running timer |
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On Tue, Apr 21, 2015 at 02:54:55PM -0700, Eric Dumazet wrote: > On Tue, 2015-04-21 at 23:32 +0200, Thomas Gleixner wrote: > > > > > Are you realizing that __mod_timer() is a massive hotpath for network > > heavy workloads? > > BTW I was considering using mod_timer_pinned() from these networking > timers (ie sk_reset_timer()) > > get_nohz_timer_target() sounds cool for laptop users, but is one cause > for bad responses to DDOS, when the selected cpu gets stressed. > > This is the reason I used mod_timer_pinned() in commit 789f558cfb3680ae > ("tcp/dccp: get rid of central timewait timer")
Hmm, that sounds unfortunate, this would wreck life for the power aware laptop/tablet etc.. people.
There is already a sysctl to manage this, is that not enough to mitigate this problem on the server side of things?
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