RE: [PATCH 1/2] nohz: Affine unpinned timers to housekeepers
From: Jiang, Yunhong
Date: Wed Sep 02 2015 - 15:04:16 EST
> -----Original Message-----
> From: Chris Metcalf [mailto:cmetcalf@xxxxxxxxxx]
> Sent: Wednesday, September 2, 2015 9:17 AM
> To: Mike Galbraith; Frederic Weisbecker
> Cc: Jiang, Yunhong; Ingo Molnar; Peter Zijlstra; LKML; Vatika Harlalka; Thomas
> Gleixner; Preeti U Murthy; Christoph Lameter; Paul E . McKenney
> Subject: Re: [PATCH 1/2] nohz: Affine unpinned timers to housekeepers
> On 09/02/2015 05:38 AM, Mike Galbraith wrote:
> > IMHO, nohz_full -> cpu_isolated_map removal really wants to happen.
> > NO_HZ_FULL_ALL currently means "Woohoo, next stop NR_CPUS=0".
> Yeah, the problem seems to be folks who use it as a kind of
> "hey, maybe this gives me some optimization boost somewhere"
> kind of setting. Did we ever hear actual use cases for people who
> benefited from running nohz_full on cpus with an active scheduler,
> i.e. no isolcpus for that core? I find it hard to imagine, but, maybe...?
I think they can use cpuset instead of isolcpus, like Viresh stated https://lkml.org/lkml/2014/4/14/199 .
This patch in fact removes one gap between cpuset and isolcpus.