[Spice-commits] Changes to 'pulse'

Gerd Hoffmann kraxel at kemper.freedesktop.org
Wed Nov 10 04:46:04 PST 2010

New branch 'pulse' available with the following commits:
commit c21251936d59153c72b8c9dde8604f9199c578d6
Author: Gerd Hoffmann <kraxel at redhat.com>
Date:   Wed Oct 27 12:21:04 2010 +0200

    pulseaudio: tweak config
    Zap unused divisor field.
    Raise the buffer size default.

commit 882ed62a0a33bc2af0802578eb4df383e8306981
Author: Gerd Hoffmann <kraxel at redhat.com>
Date:   Wed Oct 27 12:18:29 2010 +0200

    pulseaudio: setup buffer attrs
    Request reasonable buffer sizes from pulseaudio.  Without this
    pa_simple_write() can block quite long and lead to dropouts,
    especially with guests which use small audio ring buffers.

commit 467d44553dd14cd3b6ea5c87bfdb1297e725f12f
Author: Gerd Hoffmann <kraxel at redhat.com>
Date:   Wed Oct 27 12:14:18 2010 +0200

    pulseaudio: process 1/4 buffer max at once
    Limit the size of data pieces processed by the pulseaudio worker
    threads.  Never ever process more than 1/4 of the buffer at once.
    Background: The buffer area currently processed by the pulseaudio thread
    is blocked, i.e. the main thread (or iothread) can't fill in more data
    there.  The buffer processing time is roughly real-time due to the
    pa_simple_write() call blocking when the output queue to the pulse
    server is full.  Thus processing big chunks at once means blocking
    a large part of the buffer for a long time.  This brings high latency
    and can lead to dropouts.
    When processing the buffer in smaller chunks the rpos handling becomes a
    problem though.  The thread reads hw->rpos without knowing whenever
    qpa_run_out has already seen the last (small) chunk processed and
    updated rpos accordingly.  There is no point in reading hw->rpos though,
    pa->rpos can be used instead.  We just need to take care to initialize
    pa->rpos before kicking the thread.

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