| Message ID | 1484227624-6740-3-git-send-email-alex.shi@linaro.org (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Thu, Jan 12, 2017 at 09:27:03PM +0800, Alex Shi wrote: > The cpu-dma PM QoS constraint impacts all the cpus in the system. There > is no way to let the user to choose a PM QoS constraint per cpu. > > The following patch exposes to the userspace a per cpu based sysfs file > in order to let the userspace to change the value of the PM QoS latency > constraint. > > This change is inoperative in its form and the cpuidle governors have to > take into account the per cpu latency constraint in addition to the > global cpu-dma latency constraint in order to operate properly. > > BTW > The pm_qos_resume_latency usage defined in > Documentation/ABI/testing/sysfs-devices-power > The /sys/devices/.../power/pm_qos_resume_latency_us attribute > contains the PM QoS resume latency limit for the given device, > which is the maximum allowed time it can take to resume the > device, after it has been suspended at run time, from a resume > request to the moment the device will be ready to process I/O, > in microseconds. If it is equal to 0, however, this means that > the PM QoS resume latency may be arbitrary. > > Signed-off-by: Alex Shi <alex.shi@linaro.org> > To: linux-kernel@vger.kernel.org > To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: linux-pm@vger.kernel.org > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Cc: Daniel Lezcano <daniel.lezcano@linaro.org> > Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> > --- > drivers/base/cpu.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > index 4c28e1a..2c3b359 100644 > --- a/drivers/base/cpu.c > +++ b/drivers/base/cpu.c > @@ -17,6 +17,7 @@ > #include <linux/of.h> > #include <linux/cpufeature.h> > #include <linux/tick.h> > +#include <linux/pm_qos.h> > > #include "base.h" > > @@ -376,6 +377,7 @@ int register_cpu(struct cpu *cpu, int num) > > per_cpu(cpu_sys_devices, num) = &cpu->dev; > register_cpu_under_node(num, cpu_to_node(num)); > + dev_pm_qos_expose_latency_limit(&cpu->dev, 0); This patch should be submitted as the last patch in the latencies constraint changes patchset IMO. It is pointless to provide an interface before a feature which is still under discussion.
On 01/17/2017 06:23 PM, Daniel Lezcano wrote: >> > >> > @@ -376,6 +377,7 @@ int register_cpu(struct cpu *cpu, int num) >> > >> > per_cpu(cpu_sys_devices, num) = &cpu->dev; >> > register_cpu_under_node(num, cpu_to_node(num)); >> > + dev_pm_qos_expose_latency_limit(&cpu->dev, 0); > This patch should be submitted as the last patch in the latencies constraint > changes patchset IMO. It is pointless to provide an interface before a > feature which is still under discussion. Thanks for comments! will fold it into next patch! -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 4c28e1a..2c3b359 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -17,6 +17,7 @@ #include <linux/of.h> #include <linux/cpufeature.h> #include <linux/tick.h> +#include <linux/pm_qos.h> #include "base.h" @@ -376,6 +377,7 @@ int register_cpu(struct cpu *cpu, int num) per_cpu(cpu_sys_devices, num) = &cpu->dev; register_cpu_under_node(num, cpu_to_node(num)); + dev_pm_qos_expose_latency_limit(&cpu->dev, 0); return 0; }
The cpu-dma PM QoS constraint impacts all the cpus in the system. There is no way to let the user to choose a PM QoS constraint per cpu. The following patch exposes to the userspace a per cpu based sysfs file in order to let the userspace to change the value of the PM QoS latency constraint. This change is inoperative in its form and the cpuidle governors have to take into account the per cpu latency constraint in addition to the global cpu-dma latency constraint in order to operate properly. BTW The pm_qos_resume_latency usage defined in Documentation/ABI/testing/sysfs-devices-power The /sys/devices/.../power/pm_qos_resume_latency_us attribute contains the PM QoS resume latency limit for the given device, which is the maximum allowed time it can take to resume the device, after it has been suspended at run time, from a resume request to the moment the device will be ready to process I/O, in microseconds. If it is equal to 0, however, this means that the PM QoS resume latency may be arbitrary. Signed-off-by: Alex Shi <alex.shi@linaro.org> To: linux-kernel@vger.kernel.org To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-pm@vger.kernel.org Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> --- drivers/base/cpu.c | 2 ++ 1 file changed, 2 insertions(+)