From: Arthur Marsh <arthur.marsh@in...> - 2011-02-22 10:34:12
Thanks to continued use of my PentiumII-266 machine with 384 MiB of RAM
and a Soundblaster Audigy 2 ZS (SB0350) and persistence with kernel
bisecting on a fast machine and patches supplied by Clemens Ladisch and
Andrea Archangeli, a couple of causes of slow-downs with MIDI playback
have been solved.
The first has been officially accepted into the kernel:
ALSA: hrtimer: handle delayed timer interrupts, provided by Clemens
The second, was in response to a problem after the release of the 2.6.37
"Apparently, huge page compaction disables interrupts for much too long"
(Clemens Ladisch) [note that Clemens also provided the information "The
ALSA sequencer uses either the system timer or an HR timer at 1 kHz to
deliver MIDI commands (notes); the wavetable driver requires its own
interrupts in regular 5.3 ms intervals"], and Andrea Archangeli provided
With the current git head of the Linux kernel as of last weekend, which
includes the first patch and then manually adding the second patch, I
could play a MIDI file in Rosegarden 1:10.10-2 without slowdown until I
loaded the machine to the point of the system load reaching 10.
Thanks to those who provided the patches and worked to get them accepted
into the mainline kernel.