From: Will Deacon <will.deacon@arm.com>
To: Punit Agrawal <punit.agrawal@arm.com>
Cc: kvm@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 6/7] arm64: KVM: Handle trappable TLB instructions
Date: Thu, 1 Sep 2016 15:55:25 +0100 [thread overview]
Message-ID: <20160901145525.GM6721@arm.com> (raw)
In-Reply-To: <87h9a7rhvf.fsf@e105922-lin.cambridge.arm.com>
On Fri, Aug 26, 2016 at 10:37:08AM +0100, Punit Agrawal wrote:
> > Will Deacon <will.deacon@arm.com> writes:
> >> The easiest thing to do is just TLBI VMALLE1IS for all trapped operations,
> >> but you might want to see how that performs.
> >
> > That sounds reasonable for correctness. But I suspect we'll have to do
> > more to claw back some performance. Let me run a few tests and come back
> > on this.
>
> Assuming I've correctly switched in TCR and replacing the various TLB
> operations in this patch with TLBI VMALLE1IS, there is a drop in kernel
> build times of ~5% (384s vs 363s).
What do you mean by "switched in TCR"? Why is that necessary if you just
nuke the whole thing? Is the ~5% relative to no trapping at all, or
trapping, but being selective about the operation?
Will
WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 6/7] arm64: KVM: Handle trappable TLB instructions
Date: Thu, 1 Sep 2016 15:55:25 +0100 [thread overview]
Message-ID: <20160901145525.GM6721@arm.com> (raw)
In-Reply-To: <87h9a7rhvf.fsf@e105922-lin.cambridge.arm.com>
On Fri, Aug 26, 2016 at 10:37:08AM +0100, Punit Agrawal wrote:
> > Will Deacon <will.deacon@arm.com> writes:
> >> The easiest thing to do is just TLBI VMALLE1IS for all trapped operations,
> >> but you might want to see how that performs.
> >
> > That sounds reasonable for correctness. But I suspect we'll have to do
> > more to claw back some performance. Let me run a few tests and come back
> > on this.
>
> Assuming I've correctly switched in TCR and replacing the various TLB
> operations in this patch with TLBI VMALLE1IS, there is a drop in kernel
> build times of ~5% (384s vs 363s).
What do you mean by "switched in TCR"? Why is that necessary if you just
nuke the whole thing? Is the ~5% relative to no trapping at all, or
trapping, but being selective about the operation?
Will
next prev parent reply other threads:[~2016-09-01 14:55 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-16 10:45 [RFC PATCH 0/7] Add support for monitoring guest TLB operations Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 1/7] perf/trace: Add notification for perf trace events Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-31 11:01 ` Punit Agrawal
2016-08-31 11:01 ` Punit Agrawal
2016-08-31 11:01 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 2/7] KVM: Track the pid of the VM process Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 3/7] KVM: arm/arm64: Register perf trace event notifier Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 4/7] arm64: tlbflush.h: add __tlbi() macro Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-19 13:24 ` Will Deacon
2016-08-19 13:24 ` Will Deacon
2016-08-19 13:24 ` Will Deacon
2016-08-19 13:34 ` Punit Agrawal
2016-08-19 13:34 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 5/7] arm64/kvm: hyp: tlb: use __tlbi() helper Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 6/7] arm64: KVM: Handle trappable TLB instructions Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-19 15:18 ` Will Deacon
2016-08-19 15:18 ` Will Deacon
2016-08-24 10:40 ` Punit Agrawal
2016-08-24 10:40 ` Punit Agrawal
2016-08-26 9:37 ` Punit Agrawal
2016-08-26 9:37 ` Punit Agrawal
2016-08-26 12:21 ` Marc Zyngier
2016-08-26 12:21 ` Marc Zyngier
2016-08-26 12:21 ` Marc Zyngier
2016-09-01 14:55 ` Will Deacon [this message]
2016-09-01 14:55 ` Will Deacon
2016-09-01 18:29 ` Punit Agrawal
2016-09-01 18:29 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 7/7] arm64: KVM: Enable selective trapping of " Punit Agrawal
2016-08-16 10:45 ` Punit Agrawal
2016-08-17 15:58 ` [RFC PATCH 0/7] Add support for monitoring guest TLB operations Paolo Bonzini
2016-08-17 15:58 ` Paolo Bonzini
2016-08-17 15:58 ` Paolo Bonzini
2016-08-17 17:01 ` Punit Agrawal
2016-08-17 17:01 ` Punit Agrawal
2016-08-17 17:01 ` Punit Agrawal
2016-08-17 17:02 ` Paolo Bonzini
2016-08-17 17:02 ` Paolo Bonzini
2016-08-17 17:20 ` Punit Agrawal
2016-08-17 17:20 ` Punit Agrawal
2016-08-18 7:04 ` Paolo Bonzini
2016-08-18 7:04 ` Paolo Bonzini
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