Re: [PATCH] workqueue: avoid nohz_full cores

2015-04-01 Thread Tejun Heo
On Wed, Apr 01, 2015 at 09:56:07AM +0200, Peter Zijlstra wrote: > > The problem with this is that workqueue currently doesn't distinguish > > why work items are queued on per-cpu workqueues. It can't tell > > whether being bound to local CPU is for correctness or optimization > > and thus can't br

Re: [PATCH] workqueue: avoid nohz_full cores

2015-04-01 Thread Peter Zijlstra
On Tue, Mar 31, 2015 at 03:37:45PM -0400, Tejun Heo wrote: > Hello, Chris. > > On Tue, Mar 31, 2015 at 03:25:59PM -0400, cmetc...@ezchip.com wrote: > > From: Chris Metcalf > > > > When queuing work, we should avoid queuing it on the local cpu if > > we are using WORK_CPU_UNBOUND and the local cp

Re: [PATCH] workqueue: avoid nohz_full cores

2015-03-31 Thread Tejun Heo
On Tue, Mar 31, 2015 at 10:58:41PM +0200, Frederic Weisbecker wrote: > On Tue, Mar 31, 2015 at 03:25:59PM -0400, cmetc...@ezchip.com wrote: > > From: Chris Metcalf > > > > When queuing work, we should avoid queuing it on the local cpu if > > we are using WORK_CPU_UNBOUND and the local cpu is nohz

Re: [PATCH] workqueue: avoid nohz_full cores

2015-03-31 Thread Frederic Weisbecker
On Tue, Mar 31, 2015 at 03:25:59PM -0400, cmetc...@ezchip.com wrote: > From: Chris Metcalf > > When queuing work, we should avoid queuing it on the local cpu if > we are using WORK_CPU_UNBOUND and the local cpu is nohz_full, since > the workqueue will mean a later interrupt of the nohz_full proce

Re: [PATCH] workqueue: avoid nohz_full cores

2015-03-31 Thread Tejun Heo
Hello, Chris. On Tue, Mar 31, 2015 at 03:25:59PM -0400, cmetc...@ezchip.com wrote: > From: Chris Metcalf > > When queuing work, we should avoid queuing it on the local cpu if > we are using WORK_CPU_UNBOUND and the local cpu is nohz_full, since > the workqueue will mean a later interrupt of the

[PATCH] workqueue: avoid nohz_full cores

2015-03-31 Thread cmetcalf
From: Chris Metcalf When queuing work, we should avoid queuing it on the local cpu if we are using WORK_CPU_UNBOUND and the local cpu is nohz_full, since the workqueue will mean a later interrupt of the nohz_full process that presumably would prefer continuing to have 100% of the core without int