Messages in this thread | | | Date | Fri, 03 Jun 2011 14:08:01 -0700 | From | David Daney <> | Subject | Re: [PATCH] init: skip calibration delay if previously done |
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On 06/03/2011 02:00 PM, Andrew Morton wrote: > On Tue, 24 May 2011 16:19:06 -0700 > Sameer Nanda<snanda@chromium.org> wrote: > >> For each CPU, do the calibration delay only once. For subsequent calls, >> use the cached per-CPU value of loops_per_jiffy. >> >> This saves about 200ms of resume time on dual core Intel Atom N5xx based >> systems. This helps bring down the kernel resume time on such systems from >> about 500ms to about 300ms. >> >> Signed-off-by: Sameer Nanda<snanda@chromium.org> >> --- >> init/calibrate.c | 10 +++++++++- >> 1 files changed, 9 insertions(+), 1 deletions(-) >> >> diff --git a/init/calibrate.c b/init/calibrate.c >> index 76ac919..47d3408 100644 >> --- a/init/calibrate.c >> +++ b/init/calibrate.c >> @@ -183,11 +183,18 @@ recalibrate: >> return lpj; >> } >> >> +DEFINE_PER_CPU(unsigned long, cpu_loops_per_jiffy) = { 0 }; >> + >> void __cpuinit calibrate_delay(void) >> { >> static bool printed; >> + int this_cpu = smp_processor_id(); >> >> - if (preset_lpj) { >> + if (per_cpu(cpu_loops_per_jiffy, this_cpu)) { >> + loops_per_jiffy = per_cpu(cpu_loops_per_jiffy, this_cpu); >> + pr_info("Calibrating delay loop (skipped) " >> + "already calibrated this CPU previously.. ");
That wording seems a little redundant, and there are two '.' at the end.
How about: s/"already calibrated this CPU previously.. "/", this CPU previously calibrated."/
David Daney
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