From: Clemens Ladisch <clemens@ladisch.de>
To: alberto Villa <a.villa@seletech.com>
Cc: alsa-devel@alsa-project.org
Subject: Re: Using MMAP feature
Date: Mon, 23 Jul 2012 16:46:44 +0200 [thread overview]
Message-ID: <500D63D4.10202@ladisch.de> (raw)
In-Reply-To: <500D40D5.6050606@seletech.com>
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alberto Villa wrote:
> Il 23/07/2012 12:38, Clemens Ladisch ha scritto:
>> alberto Villa wrote:
>>> Hello,
>>> I'm going to use the MMAP feature of ALSA.
>>
>> Why do you need to do this?
>
> I need to use MMAP because we are running on an embedded system and we
> want to optimize its operations.
What exactly do you want to optimize? In most cases, mmap is no faster
than snd_pcm_write; using mmap make sense only if the samples are
generated dynamically without storing them in a userspace buffer.
> It was necessary to use snd_pcm_wait() before snd_pcm_begin(), may be
> this the reason?
If you never wait, the buffer will be filled eventually.
Regards,
Clemens
prev parent reply other threads:[~2012-07-23 14:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-23 7:13 Using MMAP feature alberto Villa
2012-07-23 10:38 ` Clemens Ladisch
[not found] ` <500D40D5.6050606@seletech.com>
2012-07-23 14:46 ` Clemens Ladisch [this message]
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