Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Mon, 2018-01-29 at 14:33 +0800, Lai Jiangshan wrote: > On Mon, Jan 29, 2018 at 12:41 PM, Mike Galbraith wrote: > > On Mon, 2018-01-29 at 12:15 +0800, Lai Jiangshan wrote: > >> I think adding priority boost to workqueue(flush_work()) is the best > >> way to fix the problem. > > >

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Mon, 2018-01-29 at 14:33 +0800, Lai Jiangshan wrote: > On Mon, Jan 29, 2018 at 12:41 PM, Mike Galbraith wrote: > > On Mon, 2018-01-29 at 12:15 +0800, Lai Jiangshan wrote: > >> I think adding priority boost to workqueue(flush_work()) is the best > >> way to fix the problem. > > > > I disagree,

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Mon, Jan 29, 2018 at 12:41 PM, Mike Galbraith wrote: > On Mon, 2018-01-29 at 12:15 +0800, Lai Jiangshan wrote: >> I think adding priority boost to workqueue(flush_work()) is the best >> way to fix the problem. > > I disagree, priority boosting is needlessly invasive, takes

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Mon, Jan 29, 2018 at 12:41 PM, Mike Galbraith wrote: > On Mon, 2018-01-29 at 12:15 +0800, Lai Jiangshan wrote: >> I think adding priority boost to workqueue(flush_work()) is the best >> way to fix the problem. > > I disagree, priority boosting is needlessly invasive, takes control out > of

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Mon, 2018-01-29 at 12:15 +0800, Lai Jiangshan wrote: > I think adding priority boost to workqueue(flush_work()) is the best > way to fix the problem. I disagree, priority boosting is needlessly invasive, takes control out of user hands. The kernel wanting to run a workqueue does not justify

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Mon, 2018-01-29 at 12:15 +0800, Lai Jiangshan wrote: > I think adding priority boost to workqueue(flush_work()) is the best > way to fix the problem. I disagree, priority boosting is needlessly invasive, takes control out of user hands. The kernel wanting to run a workqueue does not justify

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

I think adding priority boost to workqueue(flush_work()) is the best way to fix the problem. On Sat, Jan 27, 2018 at 1:15 PM, Wen Yang wrote: > When pinning RT threads to specific cores using CPU affinity, the > kworkers on the same CPU would starve, which may lead to some

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

I think adding priority boost to workqueue(flush_work()) is the best way to fix the problem. On Sat, Jan 27, 2018 at 1:15 PM, Wen Yang wrote: > When pinning RT threads to specific cores using CPU affinity, the > kworkers on the same CPU would starve, which may lead to some kind > of priority

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Sat, 2018-01-27 at 10:31 +0100, Mike Galbraith wrote: > On Sat, 2018-01-27 at 13:15 +0800, Wen Yang wrote: > > When pinning RT threads to specific cores using CPU affinity, the > > kworkers on the same CPU would starve, which may lead to some kind > > of priority inversion. In that case, the RT

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Sat, 2018-01-27 at 10:31 +0100, Mike Galbraith wrote: > On Sat, 2018-01-27 at 13:15 +0800, Wen Yang wrote: > > When pinning RT threads to specific cores using CPU affinity, the > > kworkers on the same CPU would starve, which may lead to some kind > > of priority inversion. In that case, the RT

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Sat, 2018-01-27 at 13:15 +0800, Wen Yang wrote: > When pinning RT threads to specific cores using CPU affinity, the > kworkers on the same CPU would starve, which may lead to some kind > of priority inversion. In that case, the RT threads would also > suffer high performance impact. ... >

Re: [RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

On Sat, 2018-01-27 at 13:15 +0800, Wen Yang wrote: > When pinning RT threads to specific cores using CPU affinity, the > kworkers on the same CPU would starve, which may lead to some kind > of priority inversion. In that case, the RT threads would also > suffer high performance impact. ... >

[RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

When pinning RT threads to specific cores using CPU affinity, the kworkers on the same CPU would starve, which may lead to some kind of priority inversion. In that case, the RT threads would also suffer high performance impact. The priority inversion looks like, CPU 0: libvirtd acquired

[RFC PATCH V5 5/5] workqueue: introduce a way to set workqueue's scheduler

When pinning RT threads to specific cores using CPU affinity, the kworkers on the same CPU would starve, which may lead to some kind of priority inversion. In that case, the RT threads would also suffer high performance impact. The priority inversion looks like, CPU 0: libvirtd acquired