diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2017-05-22 15:53:02 +1000 |
|---|---|---|
| committer | Stewart Smith <stewart@linux.vnet.ibm.com> | 2017-06-06 20:49:06 +1000 |
| commit | 05b8834b5a4ff9bd14548594700d354bc4486c5c (patch) | |
| tree | bd6c90151fada7ab78a0dc1be3ffcbe319ca94d9 /core/timer.c | |
| parent | db9c1422002c1333fd09177d32edb8c2003fb4ea (diff) | |
| download | skiboot-05b8834b5a4ff9bd14548594700d354bc4486c5c.zip skiboot-05b8834b5a4ff9bd14548594700d354bc4486c5c.tar.gz skiboot-05b8834b5a4ff9bd14548594700d354bc4486c5c.tar.bz2 | |
Convert important polling loops to spin at lowest SMT priority
The pattern of calling cpu_relax() inside a polling loop does
not suit the powerpc SMT priority instructions. Prefrred is to
set a low priority then spin until break condition is reached,
then restore priority.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[stewart@linux.vnet.ibm.com: fixup lpc-uart wait_tx_room() and unit test]
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Diffstat (limited to 'core/timer.c')
| -rw-r--r-- | core/timer.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/core/timer.c b/core/timer.c index 7548996..4b5925f 100644 --- a/core/timer.c +++ b/core/timer.c @@ -45,7 +45,10 @@ static void __sync_timer(struct timer *t) while (t->running) { unlock(&timer_lock); - cpu_relax(); + smt_lowest(); + while (t->running) + barrier(); + smt_medium(); /* Should we call the pollers here ? */ lock(&timer_lock); } |