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?