[POWERPC] spusched: Dynamic timeslicing for SCHED_OTHER

Enable preemptive scheduling for non-RT contexts.

We use the same algorithms as the CPU scheduler to calculate the time
slice length, and for now we also use the same timeslice length as the
CPU scheduler. This might be not enough for good performance and can be
changed after some benchmarking.

Note that currently we do not boost the priority for contexts waiting
on the runqueue for a long time, so contexts with a higher nice value
could starve ones with less priority.  This could easily be fixed once
the rework of the spu lists that Luke and I discussed is done.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 1 insertions, 3 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 8068171dfa9c..fddc59c204b5 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -31,8 +31,6 @@
 #include <asm/spu_csa.h>
 #include <asm/spu_info.h>
 
-#define SPU_DEF_TIMESLICE	100
-
 /* The magic number for our file system */
 enum {
 	SPUFS_MAGIC = 0x23c9b64e,
@@ -82,7 +80,6 @@ struct spu_context {
  	struct list_head rq;
 	unsigned int time_slice;
 	unsigned long sched_flags;
-	unsigned long rt_priority;
 	int policy;
 	int prio;
 };
@@ -197,6 +194,7 @@ void spu_acquire_saved(struct spu_context *ctx);
 int spu_activate(struct spu_context *ctx, unsigned long flags);
 void spu_deactivate(struct spu_context *ctx);
 void spu_yield(struct spu_context *ctx);
+void spu_set_timeslice(struct spu_context *ctx);
 int __init spu_sched_init(void);
 void __exit spu_sched_exit(void);