Messages in this thread |  | | Date | Thu, 16 Jan 2025 16:30:36 +0800 | | Subject | Re: [PATCH 2/2] cpufreq: Introduce a more generic way to set default per-policy boost flag | | From | "zhenglifeng (A)" <> |
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On 2025/1/16 14:54, Viresh Kumar wrote:
> On 15-01-25, 18:01, Lifeng Zheng wrote: >> In cpufreq_online() of cpufreq.c, the per-policy boost flag is already set >> to mirror the cpufreq_driver boost during init but using freq_table to >> judge if the policy has boost frequency. There are two drawbacks to this >> approach: >> >> 1. It doesn't work for the cpufreq drivers that do not use a frequency >> table. For now, acpi-cpufreq and amd-pstate have to enable boost in policy >> initialization. And cppc_cpufreq never set policy to boost when going >> online no matter what the cpufreq_driver boost flag is. >> >> 2. If the cpu goes offline when cpufreq_driver boost enabled and then goes >> online when cpufreq_driver boost disabled, the per-policy boost flag will >> unreasonably remain true. > > Yeah, this is a problem. I agree. If the global boost is disabled, > then boost shouldn't be allowed for any of the policies. > >> Running set_boost at the end of the online process is a more generic way >> for all cpufreq drivers. >> >> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com> >> --- >> drivers/cpufreq/cpufreq.c | 16 ++++++++++++---- >> 1 file changed, 12 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >> index 03ae879d50b9..867bda3decfd 100644 >> --- a/drivers/cpufreq/cpufreq.c >> +++ b/drivers/cpufreq/cpufreq.c >> @@ -1409,10 +1409,6 @@ static int cpufreq_online(unsigned int cpu) >> goto out_free_policy; >> } >> >> - /* Let the per-policy boost flag mirror the cpufreq_driver boost during init */ >> - if (cpufreq_boost_enabled() && policy_has_boost_freq(policy)) >> - policy->boost_enabled = true; >> - >> /* >> * The initialization has succeeded and the policy is online. >> * If there is a problem with its frequency table, take it >> @@ -1576,6 +1572,18 @@ static int cpufreq_online(unsigned int cpu) >> if (new_policy && cpufreq_thermal_control_enabled(cpufreq_driver)) >> policy->cdev = of_cpufreq_cooling_register(policy); >> >> + /* Let the per-policy boost flag mirror the cpufreq_driver boost during init */ >> + if (cpufreq_boost_supported()) { >> + policy->boost_enabled = cpufreq_boost_enabled(); >> + ret = cpufreq_driver->set_boost(policy, policy->boost_enabled); > > Maybe we can optimize here and not call set_boost() if policy's > boost_enabled is not changing at all. > if (policy->boost_enabled != cpufreq_boost_enabled()) { > policy->boost_enabled = cpufreq_boost_enabled(); > ret = cpufreq_driver->set_boost(policy, policy->boost_enabled); > ... > }
Makes sense. Thanks.
> > After this patch, maybe you should simplify the drivers as well, which > take care of enabling/boost at boot time or setting this flag ?
OK. I'll try to.
> >> + if (ret) { >> + /* If the set_boost fails, the online operation is not affected */ >> + pr_info("%s: CPU%d: Cannot %s BOOST\n", __func__, policy->cpu, >> + policy->boost_enabled ? "enable" : "disable"); >> + policy->boost_enabled = !policy->boost_enabled; >> + } >> + } >> + >> pr_debug("initialization complete\n"); >> >> return 0; >
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