From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Leo Yan <leo.yan@linaro.org>, Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
John Garry <john.garry@huawei.com>,
linux-kernel@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Suleiman Souhlal <suleiman@google.com>,
Namhyung Kim <namhyung@kernel.org>, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv3] perf kvm: add kvm-stat for arm64
Date: Thu, 17 Sep 2020 20:00:28 +0900 [thread overview]
Message-ID: <20200917110028.GB3049@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <652f10660f09bd608b825233713f775a@kernel.org>
On (20/09/17 11:21), Marc Zyngier wrote:
> > > On Arm64, ftrace tracepoint "kvm_entry" doesn't contain the field "id"
> > > or field "vcpu_id", thus it always reads out the "id" is 0 and it is
Right, Leo, I saw that. I put "id", because there is ... well, there is
nothing we can put there. The trace points on arm64, unlike on s390 or x86,
don't contain info which can let us map trace-event to vcpu_id (even
(void *)vcpu would have been rather helpful).
> > > Essentially, this issue is caused by different archs using different
> > > format for ftrace event "kvm_entry", on x86 it contains feild
> > > "vcpu_id" but arm64 only just records "vcpu_pc".
Exactly. I wish trace-points were less of pain-points.
So 'perf kvm stat' on arm64 works, but it's not as feature rich as on other
platforms; at the same it's better than nothing, I suppose.
-ss
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next prev parent reply other threads:[~2020-09-17 11:02 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 0:36 [PATCHv3] perf kvm: add kvm-stat for arm64 Sergey Senozhatsky
2020-09-17 8:47 ` Leo Yan
2020-09-17 9:54 ` Sergey Senozhatsky
2020-09-17 10:09 ` Leo Yan
2020-09-17 10:12 ` Leo Yan
2020-09-17 10:21 ` Marc Zyngier
2020-09-17 11:00 ` Sergey Senozhatsky [this message]
2020-09-17 13:08 ` Leo Yan
2020-09-17 11:42 ` Leo Yan
2020-09-17 11:53 ` Marc Zyngier
2020-09-17 12:52 ` Leo Yan
2020-09-18 0:32 ` Sergey Senozhatsky
2020-09-18 8:20 ` Marc Zyngier
2020-09-18 10:35 ` Sergey Senozhatsky
2020-09-18 10:55 ` Marc Zyngier
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