| Message ID | 20250115100123.241110-1-zhenglifeng1@huawei.com |
|---|---|
| Headers | show |
| Series | cpufreq: Introduce a more generic way to boost when cpu is going online | expand |
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); ... } After this patch, maybe you should simplify the drivers as well, which take care of enabling/boost at boot time or setting this flag ? > + 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;
Since commit f37a4d6b4a2c ("cpufreq: Fix per-policy boost behavior on SoCs using cpufreq_boost_set_sw()") and commit 102fa9c4b439 ("cpufreq: Allow drivers to advertise boost enabled"), per-policy boost flag has already been set to mirror the cpufreq_driver boost during initialization. However, the current implementation doesn't work for all cpufreq drivers and may fail in certain situation. A more generic implementation is needed. Lifeng Zheng (2): cpufreq: Fix re-boost issue after hotplugging a cpu cpufreq: Introduce a more generic way to set default per-policy boost flag drivers/cpufreq/cpufreq.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-)