tree c1d8d4f340cf7571722b2d9019f158acd345cff4
parent 5110459f181ef1f11200bb3dec61953f08cc49e7
author Arnd Bergmann <arnd@arndb.de> 1133841146 -0500
committer Paul Mackerras <paulus@samba.org> 1136778778 +1100

[PATCH] spufs: Improved SPU preemptability [part 2].

This patch reduces lock complexity of SPU scheduler, particularly
for involuntary preemptive switches.  As a result the new code
does a better job of mapping the highest priority tasks to SPUs.

Lock complexity is reduced by using the system default workqueue
to perform involuntary saves.  In this way we avoid nasty lock
ordering problems that the previous code had.  A "minimum timeslice"
for SPU contexts is also introduced.  The intent here is to avoid
thrashing.

While the new scheduler does a better job at prioritization it
still does nothing for fairness.

From: Mark Nutter <mnutter@us.ibm.com>
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>