Commit bf8102228a8bf053051f311e5486042fe0542894
Committed by
Rafael J. Wysocki
Rafael J. Wysocki
1 parent
c4ee841f60
Exists in
ti-lsk-linux-4.1.y
and in
12 other branches
intel_pstate: Improve initial busy calculation
This change makes the busy calculation using 64 bit math which prevents overflow for large values of aperf/mperf. Cc: 3.14+ <stable@vger.kernel.org> # 3.14+ Signed-off-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Showing 1 changed file with 8 additions and 5 deletions Side-by-side Diff
drivers/cpufreq/intel_pstate.c
| ... | ... | @@ -563,16 +563,19 @@ |
| 563 | 563 | static inline void intel_pstate_calc_busy(struct cpudata *cpu, |
| 564 | 564 | struct sample *sample) |
| 565 | 565 | { |
| 566 | - int32_t core_pct; | |
| 566 | + int64_t core_pct; | |
| 567 | + int32_t rem; | |
| 567 | 568 | |
| 568 | - core_pct = div_fp(int_tofp((sample->aperf)), | |
| 569 | - int_tofp((sample->mperf))); | |
| 570 | - core_pct = mul_fp(core_pct, int_tofp(100)); | |
| 569 | + core_pct = int_tofp(sample->aperf) * int_tofp(100); | |
| 570 | + core_pct = div_u64_rem(core_pct, int_tofp(sample->mperf), &rem); | |
| 571 | 571 | |
| 572 | + if ((rem << 1) >= int_tofp(sample->mperf)) | |
| 573 | + core_pct += 1; | |
| 574 | + | |
| 572 | 575 | sample->freq = fp_toint( |
| 573 | 576 | mul_fp(int_tofp(cpu->pstate.max_pstate * 1000), core_pct)); |
| 574 | 577 | |
| 575 | - sample->core_pct_busy = core_pct; | |
| 578 | + sample->core_pct_busy = (int32_t)core_pct; | |
| 576 | 579 | } |
| 577 | 580 | |
| 578 | 581 | static inline void intel_pstate_sample(struct cpudata *cpu) |
