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From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: "Wangnan (F)" <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	linux-kernel@vger.kernel.org, He Kuang <hekuang@huawei.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Namhyung Kim <namhyung@kernel.org>, Zefan Li <lizefan@huawei.com>,
	pi3orama@163.com
Subject: Re: [PATCH 02/17] perf tools: Add evlist channel helpers
Date: Wed, 18 May 2016 10:23:58 -0300	[thread overview]
Message-ID: <20160518132358.GB2370@redhat.com> (raw)
In-Reply-To: <573BE12F.5020603@huawei.com>

Em Wed, May 18, 2016 at 11:27:43AM +0800, Wangnan (F) escreveu:
> On 2016/5/13 21:05, Arnaldo Carvalho de Melo wrote:
> >Em Fri, May 13, 2016 at 07:55:59AM +0000, Wang Nan escreveu:
> >> Channels hold different groups of evsels which configured
> >> differently. It will be used for overwritable evsels, which allows
> >> perf

> >why not use multiple evlists? An "evlist" is a "list of evsels", why do
> >we need yet another way of grouping evlists?
 
> There's an assumption all over perf that there's only one evlist: in
> 'struct record' there's an 'evlist' pointer, in 'struct session'
> there's also an 'evlist' pointer.

Well, at some point there were none, and multiple tools used multiple
ways to deal with lists of events :-)

> Trying to change them to an array results in 181 errors, so I think
> fundamentally moving to multiple evlists is nearly impossible.

Well, in the next paragraph you give it some hope :-)
 
> Now I'm thinking introducing auxiliary evlists to perf record. We
> still obey one evlist assumption, only creates separated evlists for
> mmap.

Ok, that may be the way to go, i.e. linking evlists somehow for some
specific use cases, i.e. consuming events from multiple evlists,
probably sorting them via the ordered_events class, etc.

I have to review this more deeply to try and come with suggestions :-\

- Arnaldo

  reply	other threads:[~2016-05-18 13:24 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-13  7:55 [PATCH 00/17] perf tools: Support overwritable ring buffer Wang Nan
2016-05-13  7:55 ` [PATCH 01/17] perf tools: Extract __perf_evlist__mmap_read() Wang Nan
2016-05-13 13:03   ` Arnaldo Carvalho de Melo
2016-05-13  7:55 ` [PATCH 02/17] perf tools: Add evlist channel helpers Wang Nan
2016-05-13 13:05   ` Arnaldo Carvalho de Melo
2016-05-18  3:27     ` Wangnan (F)
2016-05-18 13:23       ` Arnaldo Carvalho de Melo [this message]
2016-05-13  7:56 ` [PATCH 03/17] perf tools: Automatically add new channel according to evlist Wang Nan
2016-05-13  7:56 ` [PATCH 04/17] perf tools: Operate multiple channels Wang Nan
2016-05-13  7:56 ` [PATCH 05/17] perf record: Prevent reading invalid data in record__mmap_read Wang Nan
2016-05-13  7:56 ` [PATCH 06/17] perf tools: Squash overwrite setting into channel Wang Nan
2016-05-13  7:56 ` [PATCH 07/17] perf record: Don't read from and poll overwrite channel Wang Nan
2016-05-13  7:56 ` [PATCH 08/17] perf record: Don't poll on " Wang Nan
2016-05-13 13:12   ` Arnaldo Carvalho de Melo
2016-05-16  3:18     ` Wangnan (F)
2016-05-13  7:56 ` [PATCH 09/17] perf tools: Detect avalibility of write_backward Wang Nan
2016-05-13 13:08   ` Arnaldo Carvalho de Melo
2016-05-20 15:31     ` Wangnan (F)
2016-05-20 15:39       ` Arnaldo Carvalho de Melo
2016-05-13  7:56 ` [PATCH 10/17] perf tools: Enable overwrite settings Wang Nan
2016-05-16 13:38   ` Arnaldo Carvalho de Melo
2016-05-13  7:56 ` [PATCH 11/17] perf tools: Set write_backward attribut bit for overwrite events Wang Nan
2016-05-13  7:56 ` [PATCH 12/17] perf tools: Record fd into perf_mmap Wang Nan
2016-05-13  7:56 ` [PATCH 13/17] perf tools: Add API to pause a channel Wang Nan
2016-05-13  7:56 ` [PATCH 14/17] perf record: Rename variable to make code clear Wang Nan
2016-05-13  7:56 ` [PATCH 15/17] perf record: Read from backward ring buffer Wang Nan
2016-05-13  7:56 ` [PATCH 16/17] perf record: Toggle overwrite ring buffer for reading Wang Nan
2016-05-13  7:56 ` [PATCH 17/17] perf tools: Don't warn about out of order event if write_backward is used Wang Nan

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