From: Paolo Bonzini <pbonzini@redhat.com>
To: Punit Agrawal <punit.agrawal@arm.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
Marc Zyngier <marc.zyngier@arm.com>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [RFC PATCH 0/7] Add support for monitoring guest TLB operations
Date: Wed, 17 Aug 2016 19:02:32 +0200 [thread overview]
Message-ID: <a553745d-a527-b2ba-7cfa-f688786d5dc3@redhat.com> (raw)
In-Reply-To: <87fuq3tjmv.fsf@e105922-lin.cambridge.arm.com>
On 17/08/2016 19:01, Punit Agrawal wrote:
>> Can you explain what this is used for? In other words, why would this
>> be used instead of just running perf in the guest?
>
> As TLB maintenance operations are synchronised in hardware, they can
> impact performance beyond the guest. The operations generate traffic on
> the interconnect and depending on the implementation, they can also
> affect the remote TLB's translation bandwidth.
>
> These patches are useful on systems where the host and guest are
> controlled by different users - the guest could be running arbitrary
> software.
>
> Having the ability to monitor the usage of guest TLB invalidations in
> the host can be useful to diagnose performance issues on such systems.
Are there hardware performance counters for these operations?
Paolo
next prev parent reply other threads:[~2016-08-17 17:02 UTC|newest]
Thread overview: 22+ 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 ` [RFC PATCH 1/7] perf/trace: Add notification for perf trace events 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 ` [RFC PATCH 3/7] KVM: arm/arm64: Register perf trace event notifier Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 4/7] arm64: tlbflush.h: add __tlbi() macro Punit Agrawal
2016-08-19 13:24 ` Will Deacon
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 ` [RFC PATCH 6/7] arm64: KVM: Handle trappable TLB instructions Punit Agrawal
2016-08-19 15:18 ` Will Deacon
2016-08-24 10:40 ` Punit Agrawal
2016-08-26 9:37 ` Punit Agrawal
2016-08-26 12:21 ` Marc Zyngier
2016-09-01 14:55 ` Will Deacon
2016-09-01 18:29 ` Punit Agrawal
2016-08-16 10:45 ` [RFC PATCH 7/7] arm64: KVM: Enable selective trapping of " Punit Agrawal
2016-08-17 15:58 ` [RFC PATCH 0/7] Add support for monitoring guest TLB operations Paolo Bonzini
2016-08-17 17:01 ` Punit Agrawal
2016-08-17 17:02 ` Paolo Bonzini [this message]
2016-08-17 17:20 ` Punit Agrawal
2016-08-18 7:04 ` Paolo Bonzini
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