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Date: Tue, 02 Jul 2013 16:03:45 +0900 From: Chanwoo Choi <cw00.choi@...sung.com> To: Viresh Kumar <viresh.kumar@...aro.org> Cc: rjw@...k.pl, linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, cpufreq@...r.kernel.org, kyungmin.park@...sung.com, myungjoo.ham@...sung.com Subject: Re: [PATCH v4] cpufreq: stats: Add 'load_table' debugfs file to show accumulated data of CPUs On 07/02/2013 03:44 PM, Chanwoo Choi wrote: > On 06/28/2013 07:13 PM, Viresh Kumar wrote: >> On 28 June 2013 14:52, Chanwoo Choi <cw00.choi@...sung.com> wrote: >>> On 06/28/2013 05:18 PM, Viresh Kumar wrote: >>>> On 28 June 2013 13:18, Chanwoo Choi <cw00.choi@...sung.com> wrote: >> >>>> Can you describe a bit about the layout this will create in debugfs? >>>> I thought you will have a load_table file per policy->cpu ?? >>>> >>> >>> The debugfs_cpufreq is debugfs root directory (/sys/kernel/debug/cpufreq) >> >> Which you are creating anyway in your patch. >> >>> and debugfs_cpufreq has many child directory for Per-CPU debugfs according to NR_CPUS number (/sys/kernel/debug/cpufreq/cpuX). >> >> Even you are creating this only for policy->cpu >> >>> Finally, Per-CPU debugfs create load_table debugfs file (/sys/kernel/debug/cpufreq/cpuX/load_table). >>> >>> For example, only CPU0 create sysfs directory and file (/sys/devices/system/cpu/cpu0/cpufreq) >>> and then other CPUx create link of created sysfs directory by CPU0 in cpufreq_add_dev_symlink(). >> >> This isn't how its happening now. You aren't creating any links. > > You're right. This patch didn't create link for CPU1/2/3. > >> >>> So, I'm considering whether to create link of CPUx's debugfs file except for CPU0 as sysfs file. >>> - /sys/kernel/debug/cpufreq/cpu1/ >>> - /sys/kernel/debug/cpufreq/cpu2/ >>> - /sys/kernel/debug/cpufreq/cpu3/ >> >> Yes please. > > OK. I'll create link for CPU1,2,3 if all CPUs is included in one cluster. > > I explain the sequence for creating sysfs file of CPU0/1/2/3. > There are difference about sysfs file. Only, CPU0 creates sysfs file > and then CPU1/2/3 create a link to CPU0 sysfs file. If we want to create > debugfs link for CPU1/2/3, I should have to create debugfs file for CPU0 / I made wrong sentence and then change it. : I should have to debugfs -> I should have to create debugfs file > debugfs link for CPU1/2/3 when cpufreq_register_driver() is operated. > This proposal won't always remove debugfs file for cpufreq when user change > cpufreq governor from ondemand/conservative to performance/powersave. > > So, I suggest that cpufreq core executes dbs_check_cpu() to calculate > CPUx load when cpufreq governor is performance/powersave. While maintaing > same cpu frequency on performance/powersave governor, there are different > power-consumption according to CPUx load. I think we need to check CPUs load > on peformance/powersave governor. > > [Flow sequence for CPU0] > cpufreq_register_driver() > ->subsys_interface_register() > -->sif->add_dev() > ---> cpufreq_add_dev() > ----> cpufreq_add_policy_cpu() > -----> sysfs_create_link(&dev->kboj, &policy->kobj, "cpufreq"); : Create sysfs file (/sys/devices/system/cpu/cpu0/cpufreq) > > [Flow sequence for CPU1/2/3] > cpufreq_register_driver() > ->subsys_interface_register() > -->sif->add_dev() > ---> cpufreq_add_dev() > ----> cpufreq_add_policy_cpu() > -----> cpufreq_add_dev_interface(cpu, ...) > ------> cpufreq_add_dev_symlink(cpu, ...) : Create sysfs link about CPU0 sysfs file(/sys/devices/system/cpu/cpu0/cpufreq) > >> >>> - A number of online CPU is 4 >>> Time(ms) Old Freq(Hz) New Freq(Hz) CPU0 CPU1 CPU2 CPU3 >>> 23165 200000 200000 2 0 0 0 >>> 23370 200000 200000 2 0 0 0 >>> 23575 200000 200000 2 0 1 0 >>> 23640 200000 200000 5 1 1 0 >>> 23780 200000 200000 3 0 1 0 >>> 23830 200000 200000 7 1 0 0 >>> 23985 200000 200000 1 0 0 0 >>> 24190 200000 200000 2 0 1 1 >>> 24385 200000 200000 2 0 0 0 >>> 24485 200000 200000 6 0 1 0 >>> >>> - A number of online CPU is 2 >>> Time(ms) Old Freq(Hz) New Freq(Hz) CPU0 CPU3 >>> 37615 200000 200000 0 0 >>> 37792 200000 200000 0 5 >>> 38015 200000 200000 21 8 >>> 38215 200000 200000 0 0 >>> 38275 200000 200000 5 0 >>> 38415 200000 200000 15 3 >>> 38615 200000 200000 0 0 >>> 38730 200000 200000 1 0 >>> 38945 200000 200000 0 0 >>> 39155 200000 200000 1 1 >> >> If you do the loop over for_each_cpu(cpu, policy->cpus), >> this problem will be resolved. You will see only online cpus. >> >>> I'm considering whether to check the kind of cpufreq governor for creating load_table >>> in cpufreq_stats or execute dbs_check_cpu() on performance/powersave governor to check >>> CPUx load. If you have opinion about this, I'd like to listen it. >> >> Maybe create these directories and do this stuff only when >> the first CPUFREQ_LOADCHECK notification is received inside >> cpufreq_stats.c >> >> Also don't create debug/cpufreq directory unless you have any >> stuff to be created within this directory. Like, don't create it >> if we are using performance governor for all cpus. >> > > If core create debugfs/cpufreq directory when first CPUFREQ_LOADCHECK > notification is received inside cpufreq_stats.c, CPU1/2/3 don't send > CPUFREQ_LOADCHECK notification. In result, cpufreq_stats.c couldn't > create link for /sys/kernel/debug/cpufreq/cpu[1-3]. > > Best Regards, > Chanwoo Choi > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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