@@ -516,6 +516,7 @@ static int set_time_window(struct powercap_zone *power_zone, int id,
u64 window)
{
struct rapl_domain *rd;
+ struct rapl_package *rp;
int ret = 0;
u64 max_window;
@@ -524,12 +525,18 @@ static int set_time_window(struct powercap_zone *power_zone, int id,
if (ret < 0)
goto out;
- if (window > max_window) {
+ rd = power_zone_to_rapl_domain(power_zone);
+ rp = find_package_by_id(rd->package_id);
+ /*
+ * The Intel ASDM doesn't explicitly define a minimum time window.
+ * The MSR_RAPL_POWER_UNIT register, read during initialization,
+ * does contain the smallest unit of time that can be measured.
+ */
+ if ((window > max_window) || (window < rp->time_unit)) {
ret = -EINVAL;
goto out;
}
- rd = power_zone_to_rapl_domain(power_zone);
switch (rd->rpl[id].prim_id) {
case PL1_ENABLE:
rapl_write_data_raw(rd, TIME_WINDOW1, window);
Using an small value for the time window results in a bogus value for the time window. For example, [root@intel-chiefriver-03 linux]# echo 950 > /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:1:4501502475370496 The Intel ASDM doesn't explicitly define a minimum time window. The MSR_RAPL_POWER_UNIT register, read during initialization, does specify a minimum time window unit so that can be used as a lower bound for error checking. After this change the minimum time window is properly clamped: [root@intel-chiefriver-03 linux]# echo 950 > /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" <rafael.j.wysocki@intel.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Radivoje Jovanovic <radivoje.jovanovic@intel.com> Cc: Seiichi Ikarashi <s.ikarashi@jp.fujitsu.com> Cc: Mathias Krause <minipli@googlemail.com> Cc: Ajay Thomas <ajay.thomas.david.rajamanickam@intel.com> Signed-off-by: Prarit Bhargava <prarit@redhat.com> --- drivers/powercap/intel_rapl.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)