[PATCH v2] cpufreq : powernv: Report Pmax throttling if capped below nominal frequency

Shilpasri G Bhat shilpa.bhat at linux.vnet.ibm.com
Mon Sep 14 18:31:47 AEST 2015

Log a 'critical' message if the max frequency is reduced below nominal
frequency. We already log 'info' message if the max frequency is
capped below turbo frequency. CPU should guarantee atleast nominal
frequency, but not turbo frequency in all system configurations and
environments. So report the pmax throttling with severity when Pmax is
dipped below nominal frequency.

Signed-off-by: Shilpasri G Bhat <shilpa.bhat at linux.vnet.ibm.com>
Changes from v1:
- Modified the printk messages as per Viresh's suggestion.

 drivers/cpufreq/powernv-cpufreq.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 64994e1..cb50138 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -327,8 +327,14 @@ static void powernv_cpufreq_throttle_check(void *data)
 		if (chips[i].throttled)
 			goto next;
 		chips[i].throttled = true;
-		pr_info("CPU %d on Chip %u has Pmax reduced to %d\n", cpu,
-			chips[i].id, pmsr_pmax);
+		if (pmsr_pmax < powernv_pstate_info.nominal)
+			pr_crit("CPU %d on Chip %u has Pmax reduced below nominal frequency (%d < %d)\n",
+				cpu, chips[i].id, pmsr_pmax,
+				powernv_pstate_info.nominal);
+		else
+			pr_info("CPU %d on Chip %u has Pmax reduced below turbo frequency (%d < %d)\n",
+				cpu, chips[i].id, pmsr_pmax,
+				powernv_pstate_info.max);
 	} else if (chips[i].throttled) {
 		chips[i].throttled = false;
 		pr_info("CPU %d on Chip %u has Pmax restored to %d\n", cpu,

More information about the Linuxppc-dev mailing list