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From: Greg KH <greg@kroah.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jiri Olsa <jolsa@redhat.com>,
	acme@redhat.com, mingo@elte.hu, paulus@samba.org,
	cjashfor@linux.vnet.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: [RFCv3 0/9] perf tool: parser generator for events parsing
Date: Wed, 25 Jan 2012 09:01:51 -0800	[thread overview]
Message-ID: <20120125170151.GB5311@kroah.com> (raw)
In-Reply-To: <1327488573.2614.59.camel@laptop>

On Wed, Jan 25, 2012 at 11:49:33AM +0100, Peter Zijlstra wrote:
> On Tue, 2012-01-24 at 16:53 -0800, Greg KH wrote:
> 
> > Well, what's to keep someone from exploding one of those files to go
> > over the buffer size without knowing it?
> 
> The content is known at compile time, we could put checks in. But yeah
> 4k isn't that much text..
> 
> > Even after reading the above link, I can't really understand what this
> > is being used for.  As it's sysfs files, why aren't Documentation/ABI/
> > files also being created with the patch explaining it all?
> 
> Ah, yeah, documentation, wasn't that written in C :-)
> 
> But fair enough... Anyway, the purpose is to describe the magic bits
> that go into perf_event_attr::config[012] for a particular pmu.
> 
> Basically they're the 'hardware' bitmasks we want to export, so that
> userspace can deal with sane name/value pairs.
> 
> > Again, if at all possible, sysfs should be one value per file.  Please
> > NEVER create a sysfs file that requires a parser to determine what is
> > going on in it.  It should be a simple 'read the value' type thing.
> 
> The whole purpose was to drive a parser :-) Anyway, is:
> "config:0-7,32-35" acceptable for a single file?
> 
> This means, the 'config' member of struct perf_event_attr bits 0-7,32-35
> form a bitfield whose name is then given by the filename that has this
> content.

Yes, that would be fine.

> > So yes, multiple sysfs files do make sense, the resource load should be
> > almost non-existant for new ones.
> 
> Surely all these attribute objects take more space than a few lines of
> text, but ok, I guess multiple files it is.

Great, thanks for asking.

greg k-h

  parent reply	other threads:[~2012-01-25 17:02 UTC|newest]

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-15 15:30 [RFC 0/3] perf tool: Add new event group management Jiri Olsa
2011-12-15 15:30 ` [PATCH 1/3] perf, tool: Add parser generator for events parsing Jiri Olsa
2011-12-16 14:02   ` Peter Zijlstra
2011-12-16 14:03     ` Peter Zijlstra
2011-12-20 10:31       ` Jiri Olsa
2011-12-20 10:47         ` Peter Zijlstra
2011-12-20 11:30           ` Peter Zijlstra
2011-12-20 11:39             ` Peter Zijlstra
2011-12-21 16:16               ` new syntax for perf event Jiri Olsa
2012-01-05  9:17                 ` Jiri Olsa
2012-01-05 14:10                 ` Peter Zijlstra
2012-01-09 15:28                   ` Jiri Olsa
2012-01-09 15:43                     ` Peter Zijlstra
2012-01-16 12:31                     ` [RFCv3 0/9] perf tool: parser generator for events parsing Jiri Olsa
2012-01-16 12:31                       ` [PATCH 1/9] perf, tool: Make perf_evlist__splice_list_tail global Jiri Olsa
2012-01-16 12:31                       ` [PATCH 2/9] perf, tool: Remove unused functions from debugfs object Jiri Olsa
2012-01-16 12:31                       ` [PATCH 3/9] perf, tool: Add sysfs mountpoint interface Jiri Olsa
2012-01-16 12:31                       ` [PATCH 4/9] perf, tool: Add bitmap_or function into bitmap object Jiri Olsa
2012-01-16 12:31                       ` [PATCH 5/9] perf: Add sysfs format attribute for pmu device Jiri Olsa
2012-01-23 15:13                         ` Eric W. Biederman
2012-01-23 15:33                           ` Jiri Olsa
2012-01-24 15:22                             ` Peter Zijlstra
2012-01-24 19:40                               ` Eric W. Biederman
2012-01-25  8:54                                 ` Jiri Olsa
2012-01-26 16:26                         ` Peter Zijlstra
2012-01-27 12:32                           ` Jiri Olsa
2012-01-16 12:31                       ` [PATCH 6/9] perf, tool: Add parser generator for events parsing Jiri Olsa
2012-01-24 16:02                         ` Peter Zijlstra
2012-01-25  8:42                           ` Jiri Olsa
2012-01-16 12:31                       ` [PATCH 7/9] perf, tool: Add config options support for event parsing Jiri Olsa
2012-01-16 12:31                       ` [PATCH 8/9] perf, tool: Add perf pmu object to access pmu format definition Jiri Olsa
2012-01-16 12:31                       ` [PATCH 9/9] perf, tool: Add support to specify pmu style event Jiri Olsa
2012-01-24 15:22                       ` [RFCv3 0/9] perf tool: parser generator for events parsing Peter Zijlstra
2012-01-24 16:26                       ` Peter Zijlstra
2012-01-25  0:53                         ` Greg KH
2012-01-25 10:49                           ` Peter Zijlstra
2012-01-25 14:37                             ` Jiri Olsa
2012-01-26 16:23                               ` Peter Zijlstra
2012-01-26 16:27                                 ` Greg KH
2012-01-25 17:01                             ` Greg KH [this message]
2012-01-27 14:34                       ` [PATCHv4 " Jiri Olsa
2012-01-27 14:34                         ` [PATCH 1/9] perf, tool: Make perf_evlist__splice_list_tail global Jiri Olsa
2012-02-07 19:31                           ` [tip:perf/core] perf evlist: Make splice_list_tail method public tip-bot for Jiri Olsa
2012-01-27 14:34                         ` [PATCH 2/9] perf, tool: Remove unused functions from debugfs object Jiri Olsa
2012-02-17  9:51                           ` [tip:perf/core] perf tools: " tip-bot for Jiri Olsa
2012-01-27 14:34                         ` [PATCH 3/9] perf, tool: Add sysfs mountpoint interface Jiri Olsa
2012-02-17  9:52                           ` [tip:perf/core] perf tools: " tip-bot for Jiri Olsa
2012-01-27 14:34                         ` [PATCH 4/9] perf, tool: Add bitmap_or function into bitmap object Jiri Olsa
2012-02-17  9:53                           ` [tip:perf/core] perf tools: " tip-bot for Jiri Olsa
2012-01-27 14:34                         ` [PATCH 5/9] perf: Adding sysfs group format attribute for pmu device Jiri Olsa
2012-01-27 21:08                           ` Corey Ashford
2012-01-27 21:19                             ` Peter Zijlstra
2012-02-01  0:47                               ` Corey Ashford
2012-01-30  9:52                             ` Jiri Olsa
2012-02-01  1:25                               ` Corey Ashford
2012-02-01 13:13                                 ` Jiri Olsa
2012-02-01 14:18                                   ` Peter Zijlstra
2012-02-01 14:31                                     ` Jiri Olsa
2012-02-01 14:40                                       ` Peter Zijlstra
2012-02-01 13:36                                 ` Peter Zijlstra
2012-02-02  0:33                                   ` Corey Ashford
2012-01-27 14:34                         ` [PATCH 6/9] perf, tool: Add parser generator for events parsing Jiri Olsa
2012-01-27 14:34                         ` [PATCH 7/9] perf, tool: Add config options support for event parsing Jiri Olsa
2012-01-27 14:34                         ` [PATCH 8/9] perf, tool: Add perf pmu object to access pmu format definition Jiri Olsa
2012-01-27 14:34                         ` [PATCH 9/9] perf, tool: Add support to specify pmu style event Jiri Olsa
2012-02-13 13:13                         ` [PATCHv4 0/9] perf tool: parser generator for events parsing Jiri Olsa
2012-02-14 16:28                         ` Peter Zijlstra
2012-02-14 16:43                           ` Peter Zijlstra
2012-02-14 20:20                             ` Peter Zijlstra
2012-02-14 20:57                               ` Peter Zijlstra
2012-02-14 21:03                                 ` Peter Zijlstra
2012-02-15  9:24                                   ` Jiri Olsa
2012-02-15 11:18                                     ` Peter Zijlstra
2012-02-15 13:32                                       ` Jiri Olsa
2012-02-15 13:39                                         ` Peter Zijlstra
2012-02-15  9:04                                 ` Jiri Olsa
2012-02-15 11:03                                   ` Peter Zijlstra
2011-12-22 19:32             ` [PATCH 1/3] perf, tool: Add " Vince Weaver
2011-12-19 14:37     ` Jiri Olsa
2011-12-20 10:29     ` [PATCHv2 0/2] perf tool: " Jiri Olsa
2011-12-20 10:29       ` [PATCHv2 1/2] perf, tool: Add " Jiri Olsa
2011-12-20 10:29       ` [PATCHv2 2/2] perf, tool: Add more automated tests for event parsing Jiri Olsa
2011-12-20 17:37   ` [PATCH 1/3] perf, tool: Add parser generator for events parsing Arnaldo Carvalho de Melo
2011-12-21  9:55     ` Jiri Olsa
2011-12-15 15:30 ` [PATCH 2/3] perf, tool: Add new event group management Jiri Olsa
2011-12-20 17:47   ` Arnaldo Carvalho de Melo
2011-12-20 21:20     ` Peter Zijlstra
2011-12-21 11:54       ` Arnaldo Carvalho de Melo
2011-12-15 15:30 ` [PATCH 3/3] perf, tool: Add more automated tests for event parsing Jiri Olsa
2011-12-20 17:38   ` Arnaldo Carvalho de Melo
2011-12-21  8:47   ` [tip:perf/core] perf test: " tip-bot for Jiri Olsa

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