linux-kernel - Re: [PATCH] cpufreq: intel_pstate: Fix cpuinfo_cur

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 25 Jul 2017 01:51:43 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Huaisheng HS1 Ye <yehs1@...ovo.com>
Cc:     "srinivas.pandruvada@...ux.intel.com" 
        <srinivas.pandruvada@...ux.intel.com>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: intel_pstate: Fix cpuinfo_cur_freq after performance governor changes

On Monday, July 24, 2017 03:32:47 PM Huaisheng HS1 Ye wrote:
> Hi Rafael,
> Thanks for your reply.
> 
> > On Monday, July 24, 2017 05:43:14 AM Huaisheng HS1 Ye wrote:
> > > After commit 82b4e03e01bc (intel_pstate: skip scheduler hook when in
> > > "performance" mode) Software P-state control modes couldn't get
> > > dynamic value during performance mode,
> > 
> > Please explain what you mean here.
> > 
> commit 82b4e03e01bc (intel_pstate: skip scheduler hook when in 
> "performance" mode) disables intel_pstate_set_update_util_hook when current
> policy is performance within function intel_pstate_set_policy. It leads to 
> Software P-states couldn't update sysfs interface cpuinfo_cur_freq's value 
> during performance mode, because of pstate_funcs.update_util couldn't set 
> for the given CPU.
> 
> > I guess you carried out some tests and the results were not as expected, so
> > what was the test?
> Exactly, we check the sysfs interface cpuinfo_cur_freq and the output of 
> cpupower frequency-info both with performance mode.

OK, so what about the change below:

---
 drivers/cpufreq/intel_pstate.c |    8 --------
 1 file changed, 8 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1674,13 +1674,6 @@ static int intel_pstate_init_cpu(unsigne
 	return 0;
 }
 
-static unsigned int intel_pstate_get(unsigned int cpu_num)
-{
-	struct cpudata *cpu = all_cpu_data[cpu_num];
-
-	return cpu ? get_avg_frequency(cpu) : 0;
-}
-
 static void intel_pstate_set_update_util_hook(unsigned int cpu_num)
 {
 	struct cpudata *cpu = all_cpu_data[cpu_num];
@@ -1921,7 +1914,6 @@ static struct cpufreq_driver intel_pstat
 	.setpolicy	= intel_pstate_set_policy,
 	.suspend	= intel_pstate_hwp_save_state,
 	.resume		= intel_pstate_resume,
-	.get		= intel_pstate_get,
 	.init		= intel_pstate_cpu_init,
 	.exit		= intel_pstate_cpu_exit,
 	.stop_cpu	= intel_pstate_stop_cpu,