From: Stratos Karafotis <stratosk@semaphore.gr>
To: rjw@rjwysocki.net, viresh.kumar@linaro.org, dirk.j.brandewie@intel.com
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] cpufreq: intel_pstate: Fix rounding of core_pct
Date: Wed, 11 Jun 2014 15:33:32 +0300 [thread overview]
Message-ID: <1402490012-19969-1-git-send-email-stratosk@semaphore.gr> (raw)
Local variable core_pct holds fixed point values.
When we round it we add "1" to core_pct. This has almost
no effect.
So, add int_toftp(1) to core_pct when rounding.
For example, in a given sample point (values taken from
tracepoint) with:
aperf = 5024
mperf = 10619
the core_pct is (before rounding):
core_pct = 12111
fp_toint(core_pct) = 47
After rounding:
core_pct = 12112
fp_toint(core_pct) = 47
After rounding with int_toftp(1):
core_pct = 12367
fp_toint(core_pct) = 48
Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
---
Hi Rafael,
I'm sorry for submitting again in merge window, but
I thought that maybe we need this fix for 3.16.
drivers/cpufreq/intel_pstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 4e7f492..dd80aa2 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -564,7 +564,7 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu)
core_pct = div_u64_rem(core_pct, int_tofp(sample->mperf), &rem);
if ((rem << 1) >= int_tofp(sample->mperf))
- core_pct += 1;
+ core_pct += int_tofp(1);
sample->freq = fp_toint(
mul_fp(int_tofp(cpu->pstate.max_pstate * 1000), core_pct));
--
1.9.3
next reply other threads:[~2014-06-11 12:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-11 12:33 Stratos Karafotis [this message]
2014-06-11 13:41 ` [PATCH] cpufreq: intel_pstate: Fix rounding of core_pct Doug Smythies
2014-06-11 14:08 ` Stratos Karafotis
2014-06-11 15:02 ` Doug Smythies
2014-06-11 18:28 ` Rafael J. Wysocki
2014-06-11 21:40 ` Doug Smythies
2014-06-11 21:45 ` Rafael J. Wysocki
2014-06-12 6:56 ` Doug Smythies
2014-06-11 20:20 ` Stratos Karafotis
2014-06-11 21:15 ` Doug Smythies
2014-06-12 14:35 ` Stratos Karafotis
2014-06-12 20:03 ` Rafael J. Wysocki
2014-06-13 6:49 ` Doug Smythies
2014-06-13 17:39 ` Stratos Karafotis
2014-06-13 13:48 ` Dirk Brandewie
2014-06-13 14:36 ` Doug Smythies
2014-06-13 16:56 ` Stratos Karafotis
2014-06-11 14:27 ` Doug Smythies
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