From: James Courtier-Dutton <james.dutton@gmail.com>
To: John Lindgren <john.lindgren@tds.net>
Cc: alsa-devel@alsa-project.org
Subject: Re: [PATCH] alsa-lib: snd_pcm_delay and friends do not account for a write being currently in progress
Date: Thu, 3 Jun 2010 17:34:30 +0100 [thread overview]
Message-ID: <AANLkTilcRfntO-8vmOCIlFdlLSeyNxd3fJR_8RgfmWNa@mail.gmail.com> (raw)
In-Reply-To: <1275581413.15555.2.camel@satellite>
On 3 June 2010 17:10, John Lindgren <john.lindgren@tds.net> wrote:
>
> I understand that snd_pcm_delay and snd_pcm_writei currently "interfere
> with each other" in that snd_pcm_delay returns wrong values if called
> during snd_pcm_writei. That is the problem my patch tries to correct.
> Do you disagree with this improvement? If so, why?
>
I disagree because I believe the changes are unnecessary.
The alsa api is big enough already, so adding anything extra must have
an extremely good reason for it.
snd_pcm_writei and snd_pcm_delay were always intended to be used in
the same thread.
Calling snd_pcm_writei and snd_pcm_delay at the same time is
non-deterministic so fairly pointless to do.
Adding more locks just makes another hit on performances so should be avoided.
Locks really kill performance on a multi processor SMP machine.
I would argue that modifying your program to fit in the the above
contraints is the way to go.
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next prev parent reply other threads:[~2010-06-03 16:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-02 21:29 [PATCH] alsa-lib: snd_pcm_delay and friends do not account for a write being currently in progress John Lindgren
2010-06-03 6:40 ` Clemens Ladisch
2010-06-03 14:00 ` John Lindgren
2010-06-03 14:48 ` Clemens Ladisch
2010-06-03 16:16 ` John Lindgren
2010-06-03 17:03 ` Clemens Ladisch
2010-06-03 17:51 ` John Lindgren
2010-06-03 14:40 ` [PATCH] " James Courtier-Dutton
2010-06-03 16:10 ` John Lindgren
2010-06-03 16:34 ` James Courtier-Dutton [this message]
2010-06-03 18:06 ` John Lindgren
2010-06-03 17:40 ` VDR User
2010-06-03 18:08 ` John Lindgren
2010-06-04 6:50 ` Clemens Ladisch
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