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From: Jean Delvare <khali@linux-fr.org>
To: David Howells <dhowells@redhat.com>
Cc: linux-i2c@vger.kernel.org, rostedt@goodmis.org,
	linux-kernel@vger.kernel.org,
	Wolfram Sang <wolfram@the-dreams.de>
Subject: Re: [PATCH] i2c: Add message transfer tracepoints for I2C and SMBUS
Date: Fri, 13 Dec 2013 17:53:50 +0100	[thread overview]
Message-ID: <20131213175350.0c4a95d5@endymion.delvare> (raw)
In-Reply-To: <3708.1386950736@warthog.procyon.org.uk>

On Fri, 13 Dec 2013 16:05:36 +0000, David Howells wrote:
> Jean Delvare <khali@linux-fr.org> wrote:
> 
> > One significant difference between both implementations is that the old
> > one logs before the actual transfer, while yours logs afterward. While I
> > understand this allows you to log the result of the transfer, this also
> > means you'll miss the log if the actual transaction locks the system
> > (we've seen this before.) Something to think about...
> 
> I could split each into three messages:
> 
> 	- Write request (has params & data buffer)
> 	- Read request (has params but no data buffer)
> 	- Read reply (has data buffer only)
> 
> It will make the transfer functions more complex, though, and will mean that,
> for i2c, you won't get all the replies to the messages in a batch in with the
> requests.  I can also label the messages with the index number.  Mostly I
> suspect this won't be a problem.

Fine with me, we can leave it as is and revisit if it ever is a
problem in practice.

-- 
Jean Delvare

  reply	other threads:[~2013-12-13 16:53 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-13 14:26 [PATCH] i2c: Add message transfer tracepoints for I2C and SMBUS David Howells
     [not found] ` <20131213142627.4014.42860.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2013-12-13 15:33   ` Jean Delvare
     [not found]     ` <20131213163349.4bc686c0-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org>
2013-12-13 15:48       ` Steven Rostedt
2013-12-13 16:05       ` David Howells
2013-12-13 16:53         ` Jean Delvare [this message]
2013-12-13 17:26         ` David Howells
     [not found]           ` <18214.1386955613-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2013-12-13 18:13             ` Steven Rostedt
2013-12-14  0:16           ` David Howells
     [not found]     ` <20131213104806.4fb56012-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
2013-12-13 17:04       ` David Howells
     [not found]         ` <22364.1386954254-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2013-12-13 17:39           ` Steven Rostedt

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