From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>, kvm-devel <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Bandan Das <bsd@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH] sched: introduce configurable delay before entering idle
Date: Tue, 14 May 2019 11:20:15 -0400 [thread overview]
Message-ID: <20190514152015.GM20906@char.us.oracle.com> (raw)
In-Reply-To: <20190514135022.GD4392@amt.cnet>
On Tue, May 14, 2019 at 10:50:23AM -0300, Marcelo Tosatti wrote:
> On Mon, May 13, 2019 at 05:20:37PM +0800, Wanpeng Li wrote:
> > On Wed, 8 May 2019 at 02:57, Marcelo Tosatti <mtosatti@redhat.com> wrote:
> > >
> > >
> > > Certain workloads perform poorly on KVM compared to baremetal
> > > due to baremetal's ability to perform mwait on NEED_RESCHED
> > > bit of task flags (therefore skipping the IPI).
> >
> > KVM supports expose mwait to the guest, if it can solve this?
> >
> > Regards,
> > Wanpeng Li
>
> Unfortunately mwait in guest is not feasible (uncompatible with multiple
> guests). Checking whether a paravirt solution is possible.
There is the obvious problem with that the guest can be malicious and
provide via the paravirt solution bogus data. That is it expose 0% CPU
usage but in reality be mining and using 100%.
next prev parent reply other threads:[~2019-05-14 15:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 18:56 [PATCH] sched: introduce configurable delay before entering idle Marcelo Tosatti
2019-05-07 22:15 ` Peter Zijlstra
2019-05-07 23:44 ` Marcelo Tosatti
2019-05-13 9:20 ` Wanpeng Li
2019-05-13 11:31 ` Konrad Rzeszutek Wilk
2019-05-13 11:51 ` Raslan, KarimAllah
2019-05-13 12:30 ` Boris Ostrovsky
2019-05-15 1:45 ` Wanpeng Li
2019-05-14 13:50 ` Marcelo Tosatti
2019-05-14 15:20 ` Konrad Rzeszutek Wilk [this message]
2019-05-14 17:42 ` Marcelo Tosatti
2019-05-15 1:42 ` Wanpeng Li
2019-05-15 20:26 ` Marcelo Tosatti
2019-05-15 18:42 ` Ankur Arora
2019-05-15 20:43 ` Marcelo Tosatti
2019-05-17 4:32 ` Ankur Arora
2019-05-17 17:49 ` Marcelo Tosatti
2019-05-16 1:07 ` Wanpeng Li
2019-05-17 2:06 ` Ankur Arora
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