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| author |   Anton Blanchard <anton@samba.org> | 2010-05-16 20:02:39 +0000 |
|---|---|---|
| committer |   Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-05-21 17:31:12 +1000 |
| commit | b878dc00595440586874952dd85ce9b803360b87 (patch) | |
| tree | 172832984c2ca6661cb48899c40b5734cdfa82a3 /arch/powerpc/include/asm | |
| parent | powerpc: Remove check of ibm,smt-snooze-delay OF property (diff) | |
| download | linux-dev-b878dc00595440586874952dd85ce9b803360b87.tar.xz linux-dev-b878dc00595440586874952dd85ce9b803360b87.zip | |
powerpc: Use smt_snooze_delay=-1 to always busy loop
Right now if we want to busy loop and not give up any time to the hypervisor
we put a very large value into smt_snooze_delay. This is sometimes useful
when running a single partition and you want to avoid any latencies due
to the hypervisor or CPU power state transitions. While this works, it's a bit
ugly - how big a number is enough now we have NO_HZ and can be idle for a very
long time.
The patch below makes smt_snooze_delay signed, and a negative value means loop
forever:
echo -1 > /sys/devices/system/cpu/cpu0/smt_snooze_delay
This change shouldn't affect the existing userspace tools (eg ppc64_cpu), but
I'm cc-ing Nathan just to be sure.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include/asm')
0 files changed, 0 insertions, 0 deletions