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From: David Ahern <dsahern@gmail.com>
To: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	Stanislav Fomichev <stfomichev@yandex-team.ru>
Cc: a.p.zijlstra@chello.nl, paulus@samba.org, mingo@redhat.com,
	jolsa@redhat.com, xiaoguangrong@linux.vnet.ibm.com,
	yangds.fnst@cn.fujitsu.com, adrian.hunter@intel.com,
	namhyung@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/7] perf kvm: move perf_kvm__mmap_read into session utils
Date: Mon, 23 Jun 2014 08:06:34 -0600	[thread overview]
Message-ID: <53A8346A.80905@gmail.com> (raw)
In-Reply-To: <20140620144427.GF31524@kernel.org>

On 6/20/14, 8:44 AM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jun 20, 2014 at 02:49:48PM +0400, Stanislav Fomichev escreveu:
>> It will be reused by perf trace in the following commit.
>
> I know this is needed, but one of the goals when I started builtin-trace
> was not to use perf_session at all, as it initially was just about the
> live mode.
>
> record/replay came later and ended up needing it,

perf-kvm does not use the session code because I kept tripping over the 
out of order timestamp problem. By limiting the number of events read in 
a single pass I was able to smooth out the load and avoided hitting it 
as often. As I mentioned before the final piece was using the perf_clock 
timestamp at the start of the round to ensure I never hit it.

Stanislav: are you seeing out of order timestamp errors or just trying 
to reuse the live code from perf-kvm?

David

  parent reply	other threads:[~2014-06-23 14:06 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-20 10:49 [PATCH v2 0/7] perf trace pagefaults Stanislav Fomichev
2014-06-20 10:49 ` [PATCH 1/7] perf trace: add perf_event parameter to tracepoint_handler Stanislav Fomichev
2014-06-20 10:49 ` [PATCH 2/7] perf trace: add support for pagefault tracing Stanislav Fomichev
2014-06-20 14:59   ` Arnaldo Carvalho de Melo
2014-06-20 15:49     ` Stanislav Fomichev
2014-06-20 16:11       ` Arnaldo Carvalho de Melo
2014-06-24 12:46         ` Stanislav Fomichev
2014-06-24 15:21           ` Arnaldo Carvalho de Melo
2014-06-20 10:49 ` [PATCH 3/7] perf trace: add pagefaults record and replay support Stanislav Fomichev
2014-06-20 10:49 ` [PATCH 4/7] perf trace: add pagefault statistics Stanislav Fomichev
2014-06-20 10:49 ` [PATCH 5/7] perf trace: add possibility to switch off syscall events Stanislav Fomichev
2014-06-20 10:49 ` [PATCH 6/7] perf kvm: move perf_kvm__mmap_read into session utils Stanislav Fomichev
2014-06-20 14:44   ` Arnaldo Carvalho de Melo
2014-06-20 15:07     ` Stanislav Fomichev
2014-06-20 15:25       ` Arnaldo Carvalho de Melo
2014-06-23 14:06     ` David Ahern [this message]
2014-06-23 14:14       ` Stanislav Fomichev
2014-06-20 10:49 ` [PATCH 7/7] perf trace: add events cache Stanislav Fomichev
2014-06-20 13:21 ` [PATCH v2 0/7] perf trace pagefaults Arnaldo Carvalho de Melo
2014-06-20 15:03   ` Stanislav Fomichev
2014-06-20 15:24     ` Arnaldo Carvalho de Melo
2014-06-20 16:18       ` Stanislav Fomichev
2014-06-20 18:30         ` Arnaldo Carvalho de Melo
2014-06-23 11:41           ` Stanislav Fomichev
2014-06-24 14:15             ` Arnaldo Carvalho de Melo
2014-06-23 14:00       ` David Ahern
2014-06-24  7:17   ` Namhyung Kim

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