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From: Bandan Das <bsd@redhat.com>
To: "Michael Rapoport" <RAPOPORT@il.ibm.com>
Cc: jiangshanlai@gmail.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, mst@redhat.com, tj@kernel.org
Subject: Re: vhost threading model
Date: Tue, 22 Mar 2016 15:00:50 -0400	[thread overview]
Message-ID: <jpgfuvi72xp.fsf@linux.bootlegged.copy> (raw)
In-Reply-To: <201603220712.u2M7CCfq004548@d06av03.portsmouth.uk.ibm.com> (Michael Rapoport's message of "Tue, 22 Mar 2016 09:12:08 +0200")

"Michael Rapoport" <RAPOPORT@il.ibm.com> writes:
...
>
> Well, Elvis is a _theoretical_ example that showed that I/O scheduling in 
> the vhost improves performance.
> I'm not saying we should take Evlis and try to squeeze it into the vhost, 
> I just want to say that we cannot switch vhost to use workqueues if it 
> causes performance degradation.
>
> My opinion is that we need to give it some more thought, much more 
> performance evaluation, so that we can find the best model.

Exactly, I think we are outright discarding using workqueues even
without investigating it in detail even though it would be a cleaner
implementation using a common framework and thereby more chances of
an acceptable solution for upstream.

Anyway, if we don't want to go the workqueues way for vhost, cgroups
support for workqueues is still something worth having on its own.

>> > opportunity for optimization, at least for some workloads...
>> > That said, I believe that switching vhost to use workqueues is not 
> that 
>> > good idea after all.
>> > 
>
> --
> Sincerely yours,
> Mike.
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
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  parent reply	other threads:[~2016-03-22 19:01 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-18 22:14 [RFC PATCH 0/4] cgroup aware workqueues Bandan Das
2016-03-18 22:14 ` [RFC PATCH 1/4] cgroup: Introduce a function to compare two tasks Bandan Das
2016-03-18 22:14 ` [RFC PATCH 2/4] workqueue: introduce support for attaching to cgroups Bandan Das
2016-03-18 22:14 ` [RFC PATCH 3/4] cgroup: use spin_lock_irq for cgroup match and attach fns Bandan Das
2016-03-18 22:14 ` [RFC PATCH 4/4] vhost: use workqueues for the works Bandan Das
2016-03-20 18:10 ` [RFC PATCH 0/4] cgroup aware workqueues Tejun Heo
2016-03-21 17:35   ` Bandan Das
2016-03-21  7:58 ` Michael Rapoport
2016-03-21  8:29 ` Christian Borntraeger
2016-03-21 17:49   ` Bandan Das
     [not found] ` <201603210758.u2L7wiXA028101@d06av09.portsmouth.uk.ibm.com>
2016-03-21 17:43   ` Bandan Das
2016-03-22  7:12     ` vhost threading model (was: Re: [RFC PATCH 0/4] cgroup aware workqueues) Michael Rapoport
     [not found]     ` <201603220712.u2M7CCfq004548@d06av03.portsmouth.uk.ibm.com>
2016-03-22 19:00       ` Bandan Das [this message]
2016-03-23 11:13         ` vhost threading model Michael Rapoport
     [not found] ` <201603210758.u2L7wiY9003907@d06av07.portsmouth.uk.ibm.com>
2016-03-30 17:04   ` [RFC PATCH 0/4] cgroup aware workqueues Tejun Heo
2016-03-31  6:17     ` Michael Rapoport
2016-03-31 17:14       ` Tejun Heo
2016-03-31 18:45         ` Bandan Das
2016-04-03 10:43           ` Michael Rapoport
     [not found]           ` <201604031043.u33AhpSF023771@d06av06.portsmouth.uk.ibm.com>
2016-04-04 17:00             ` Bandan Das
2016-04-03 10:43         ` Michael Rapoport
2016-05-27  9:22         ` Michael Rapoport
2016-05-27 14:17           ` Tejun Heo

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