On Mon, 2016-03-21 at 08:27 -0400, Prarit Bhargava wrote: > The MSR_PKG_POWER_INFO register (Intel ASDM, section 14.9.3 > "Package RAPL Domain") provides a maximum time window which the > system can support. This window is read-only and is currently > not examined when setting the time windows for the package. > Usually this field has lot of junk. It is not supported uniformly. The system provides this value from another ACPI element called PPCC. If supported this will be in
$ /sys/bus/pci/devices/0000:00:04.0/power_limits $ grep . * power_limit_0_max_uw:15000000 power_limit_0_min_uw:125000 power_limit_0_step_uw:1000000 power_limit_0_tmax_us:32000000 power_limit_0_tmin_us:28000000 power_limit_1_max_uw:25000000 power_limit_1_min_uw:25000000 power_limit_1_step_uw:1000000 power_limit_1_tmax_us:0 power_limit_1_tmin_us:0 Thanks, Srinivas > This patch implements get_max_time_window_us() and checks the window > when > a user attempts to set power capping for the package. > > Before the patch it was possible to set the window to, for example, > 10000 > micro seconds: > > [root@intel-chiefriver-03 rhel7]# echo 10000 > > /sys/devices/virtual/powercap/intel-rapl/intel- > rapl\:0/constraint_0_time_window_us; > egrep ^ /sys/devices/virtual/powercap/intel-rapl/intel- > rapl\:0/constraint_0_time_window_us > > /sys/devices/virtual/powercap/intel-rapl/intel- > rapl:0/constraint_0_time_window_us:1:9765 > > but from 'turbostat -d', the package is limited to 976us: > > cpu0: MSR_PKG_POWER_INFO: 0x01200168 (45 W TDP, RAPL 36 - 0 W, > 0.000977 sec.) > > (Note, there appears to be a rounding issue in turbostat which needs > to > also be fixed. Looking at the values in the register it is clear the > value is 1/1024 = 976us.) > > After the patch we are limited by the maximum time window: > > [root@intel-chiefriver-03 rhel7]# echo 10000 > > /sys/devices/virtual/powercap/intel-rapl/intel- > rapl\:0/constraint_0_time_window_us; > egrep ^ /sys/devices/virtual/powercap/intel-rapl/intel- > rapl\:0/constraint_0_time_window_us > > -bash: echo: write error: Invalid argument > /sys/devices/virtual/powercap/intel-rapl/intel- > rapl:0/constraint_0_time_window_us:1:976 > > Cc: "Rafael J. Wysocki" <[email protected]> > Cc: Prarit Bhargava <[email protected]> > Cc: Radivoje Jovanovic <[email protected]> > Cc: Seiichi Ikarashi <[email protected]> > Cc: Mathias Krause <[email protected]> > Cc: Ajay Thomas <[email protected]> > Signed-off-by: Prarit Bhargava <[email protected]> > --- > drivers/powercap/intel_rapl.c | 31 > +++++++++++++++++++++++++++++++ > drivers/powercap/powercap_sys.c | 6 ++++-- > 2 files changed, 35 insertions(+), 2 deletions(-) > > diff --git a/drivers/powercap/intel_rapl.c > b/drivers/powercap/intel_rapl.c > index 6c592dc..feb063d 100644 > --- a/drivers/powercap/intel_rapl.c > +++ b/drivers/powercap/intel_rapl.c > @@ -493,13 +493,42 @@ static int get_current_power_limit(struct > powercap_zone *power_zone, int id, > return ret; > } > > +static int get_max_time_window(struct powercap_zone *power_zone, int > id, > + u64 *data) > +{ > + struct rapl_domain *rd; > + int ret = 0; > + u64 val; > + > + get_online_cpus(); > + rd = power_zone_to_rapl_domain(power_zone); > + > + if (rapl_read_data_raw(rd, MAX_TIME_WINDOW, true, &val)) > + ret = -EIO; > + else > + *data = val; > + > + put_online_cpus(); > + return ret; > +} > + > static int set_time_window(struct powercap_zone *power_zone, int id, > u64 > window) > { > struct rapl_domain *rd; > int ret = 0; > + u64 max_window; > > get_online_cpus(); > + ret = get_max_time_window(power_zone, id, &max_window); > + if (ret < 0) > + goto out; > + > + if (window > max_window) { > + ret = -EINVAL; > + goto out; > + } > + > rd = power_zone_to_rapl_domain(power_zone); > switch (rd->rpl[id].prim_id) { > case PL1_ENABLE: > @@ -511,6 +540,7 @@ static int set_time_window(struct powercap_zone > *power_zone, int id, > default: > ret = -EINVAL; > } > +out: > put_online_cpus(); > return ret; > } > @@ -590,6 +620,7 @@ static const struct powercap_zone_constraint_ops > constraint_ops = { > .set_time_window_us = set_time_window, > .get_time_window_us = get_time_window, > .get_max_power_uw = get_max_power, > + .get_max_time_window_us = get_max_time_window, > .get_name = get_constraint_name, > }; > > diff --git a/drivers/powercap/powercap_sys.c > b/drivers/powercap/powercap_sys.c > index 14bde0d..53fad0f 100644 > --- a/drivers/powercap/powercap_sys.c > +++ b/drivers/powercap/powercap_sys.c > @@ -101,7 +101,7 @@ static ssize_t store_constraint_##_attr(struct > device *dev,\ > int err; \ > u64 value; \ > struct powercap_zone *power_zone = to_powercap_zone(dev); \ > - int id; \ > + int id, ret; \ > struct powercap_zone_constraint *pconst;\ > \ > if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \ > @@ -113,8 +113,10 @@ static ssize_t store_constraint_##_attr(struct > device *dev,\ > if (err) \ > return -EINVAL; \ > if (pconst && pconst->ops && pconst->ops->set_##_attr) { \ > - if (!pconst->ops->set_##_attr(power_zone, id, > value)) \ > + ret = pconst->ops->set_##_attr(power_zone, id, > value); \ > + if (!ret) \ > return count; \ > + return ret; \ > } \ > \ > return -ENODATA; \
