[PATCH 0/3 v6] cpufreq: Add 'load_table' debugfs file to show collecedCPUs load
From: Chanwoo Choi
Date: Thu Jul 18 2013 - 07:18:10 EST
This patchset add 'load_table' debugfs file to provide collected CPUs data.
The load_table debugfs file gives below CPU datas.
- measured time
- old CPU frequency
- new CPU frequency
- Per-CPU load
These data will mean the change of CPU frequency according to CPUs load at
specific measured time. Also, the user can determine the storage size of colleced
CPUs data. The range is from 10 to 1000. The patch3 explain the detailed
description of load_table debugfs file.
Changes since v5:
[patch1/3]
- Refactoring patch v4
- Create again symbolic link of debugfs directory when first CPU dev is removed
(In this case, many CPUs share only one cpufreq policy)
[patch2/3]
- Determine index value of policy->cpu_debugfs[] according to
cpumask_weight(policy->cpus) value
- Bug fix, store 'policy->cpu' to 'freq->cpu' before notify
CPUFREQ_LOADCHECK notification
[patch3/3]
- Add description of test case
Changes since v4:
[patch2/3]
- Reset the data of CPUs load when cpufreq governor is changed
- Move code about creating debugfs directory to below first patch
: [PATCH 1/2] cpufreq: Add debugfs directory for cpufreq
--
I sent only one patch before v4
and then I divided one patch in 3 patches after v4.
Changes since v3:
- Extend a range of accumulated data (10 ~ 1000)
- Add unit information of time/freq and align 'Time' field as left for readability
- Use CONFIG_CPU_FREQ_STAT depdendency instead of CONFIG_CPU_FREQ_STAT_DETATILS
- Initialize load of offline CPUx as zero(0)
- Create/remove debugfs root directory on cpufreq_stats_init/exit() because
debugfs root is used on all CPUs.
Changes since v2:
- Code clean according to Viresh Kumar's comment
- Show both old frequency and new frequency on 'load_table' debugfs file
- Change debufs file patch as below
old: /sys/kernel/debugfs/cpufreq/load_table
new: /sys/kernel/debugfs/cpufreq/cpuX/load_table
Changes since v1:
- Set maximum storage size to save CPUs load on Kconfig
- Use spinlock to synchronize read/write operation for CPUs load
- Use local variable instead of global variable(struct cpufreq_freqs *freqs)
- Use pointer of data structure to get correct size of data structure
in sizeof() macro instead of structure name
: sizeof(struct cpufreq_freqs) -> sizeof(*stat->load_table)
- Change time unit from nanosecond to microsecond
- Remove unnecessary memory copy
Thanks,
Chanwoo Choi
[Test Result]
- condition : Samsung SoC Exynos4412 (all CPUs share one voltage/frequency)
1. [ONDEMAND governor, the number of online CPU is 4]
-sh-4.1# ls -al /sys/kernel/debug/cpufreq/
total 0
drwxr-xr-x 3 root root 0 Jan 1 09:00 .
drwx------ 28 root root 0 Jan 1 09:00 ..
drwxr-xr-x 2 root root 0 Jan 1 09:00 cpu0
lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu1 -> ./cpu0
lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu2 -> ./cpu0
lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu3 -> ./cpu0
-sh-4.1# cat /sys/kernel/debug/cpufreq/cpu0/load_table
Time(ms) Old Freq(Hz) New Freq(Hz) CPU0 CPU1 CPU2 CPU3
135720 400000 400000 56 52 53 91
135820 400000 400000 67 65 83 64
135920 400000 400000 67 66 77 67
136020 400000 1100000 40 41 98 37
136120 1100000 600000 21 24 43 32
136220 600000 600000 29 36 25 87
136320 600000 600000 83 45 44 44
136420 600000 300000 38 27 37 45
136520 300000 1100000 48 45 49 97
136620 1100000 900000 28 38 26 74
2. [ONDEMAND governor, the number of online CPU is 3]
-sh-4.1# ls -al /sys/kernel/debug/cpufreq/
total 0
drwxr-xr-x 3 root root 0 Jan 1 09:02 .
drwx------ 28 root root 0 Jan 1 09:00 ..
drwxr-xr-x 2 root root 0 Jan 1 09:00 cpu0
lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu1 -> ./cpu0
lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu3 -> ./cpu0
-sh-4.1# cat /sys/kernel/debug/cpufreq/cpu0/load_table
Time(ms) Old Freq(Hz) New Freq(Hz) CPU0 CPU1 CPU3
156720 200000 200000 60 60 60
156820 200000 200000 61 58 60
156930 200000 200000 61 61 59
157020 200000 200000 61 67 61
157120 200000 200000 63 66 63
157230 200000 200000 61 61 60
157320 200000 200000 60 63 61
157420 200000 200000 61 61 60
157520 200000 200000 69 69 69
157620 200000 200000 93 95 94
<s/devices/system/cpu/cpu0/cpufreq/scaling_governor
3. [PERFORMANCE governor, the number of online CPU is 3]
-sh-4.1# echo performance > /sys/kernel/debug/cpufreq/cpu0/cpufreq/scaling_governor
-sh-4.1# cat /sys/kernel/debug/cpufreq/cpu0/load_table
Time(ms) Old Freq(Hz) New Freq(Hz) CPU0 CPU1 CPU3
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
Chanwoo Choi (3):
cpufreq: Add debugfs directory for cpufreq
cpufreq: stats: Add 'load_table' debugfs file to show accumulated data of CPUs
Documentation: cpufreq: load_table: Update load_table debugfs file documentation
Documentation/cpu-freq/cpufreq-stats.txt | 40 ++++-
drivers/cpufreq/Kconfig | 6 +
drivers/cpufreq/cpufreq.c | 181 ++++++++++++++++++++++
drivers/cpufreq/cpufreq_governor.c | 14 ++
drivers/cpufreq/cpufreq_stats.c | 258 ++++++++++++++++++++++++++++---
include/linux/cpufreq.h | 7 +
6 files changed, 478 insertions(+), 28 deletions(-)
--
1.8.0
--
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