[PATCH v4 3/4] cpufreq: powernv: Add a trace print for the throttle event

From: Shilpasri G Bhat
Date: Mon Jan 11 2016 - 15:57:15 EST


Record the throttle event with a trace print replacing the printk,
except for events like throttling below nominal and occ reset
event which print a warning message.

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
---
Changes from v3:
- Separate this patch to contain trace_point changes
- Move struct chip member 'restore' of type bool above 'mask' to reduce
structure padding.

No changes from v2.

Changes from v1:
- As suggested by Paul Clarke replaced char * throttle_reason[][30] by
const char * const throttle_reason[].

drivers/cpufreq/powernv-cpufreq.c | 95 ++++++++++++++++++++-------------------
1 file changed, 49 insertions(+), 46 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 597a084..c98a6e7 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -28,6 +28,7 @@
#include <linux/of.h>
#include <linux/reboot.h>
#include <linux/slab.h>
+#include <trace/events/power.h>

#include <asm/cputhreads.h>
#include <asm/firmware.h>
@@ -44,12 +45,22 @@
static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
static bool rebooting, throttled, occ_reset;

+static const char * const throttle_reason[] = {
+ "No throttling",
+ "Power Cap",
+ "Processor Over Temperature",
+ "Power Supply Failure",
+ "Over Current",
+ "OCC Reset"
+};
+
static struct chip {
unsigned int id;
bool throttled;
+ bool restore;
+ u8 throt_reason;
cpumask_t mask;
struct work_struct throttle;
- bool restore;
} *chips;

static int nr_chips;
@@ -310,41 +321,49 @@ static inline unsigned int get_nominal_index(void)
return powernv_pstate_info.max - powernv_pstate_info.nominal;
}

-static void powernv_cpufreq_throttle_check(void *data)
+static void powernv_cpufreq_check_pmax(void)
{
unsigned int cpu = smp_processor_id();
unsigned int chip_id = pir_to_chip_id(hard_smp_processor_id());
- unsigned long pmsr;
int pmsr_pmax, i;

- pmsr = get_pmspr(SPRN_PMSR);
+ pmsr_pmax = (s8)PMSR_MAX(get_pmspr(SPRN_PMSR));

for (i = 0; i < nr_chips; i++)
if (chips[i].id == chip_id)
break;

- /* Check for Pmax Capping */
- pmsr_pmax = (s8)PMSR_MAX(pmsr);
if (pmsr_pmax != powernv_pstate_info.max) {
if (chips[i].throttled)
- goto next;
+ return;
+
chips[i].throttled = true;
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);
+ pr_warn_once("CPU %d on Chip %u has Pmax reduced below nominal frequency (%d < %d)\n",
+ cpu, chips[i].id, pmsr_pmax,
+ powernv_pstate_info.nominal);
+
+ trace_powernv_throttle(chips[i].id,
+ throttle_reason[chips[i].throt_reason],
+ pmsr_pmax);
} else if (chips[i].throttled) {
chips[i].throttled = false;
- pr_info("CPU %d on Chip %u has Pmax restored to %d\n", cpu,
- chips[i].id, pmsr_pmax);
+ trace_powernv_throttle(chips[i].id,
+ throttle_reason[chips[i].throt_reason],
+ pmsr_pmax);
}
+}
+
+static void powernv_cpufreq_throttle_check(void *data)
+{
+ unsigned long pmsr;
+
+ pmsr = get_pmspr(SPRN_PMSR);
+
+ /* Check for Pmax Capping */
+ powernv_cpufreq_check_pmax();

/* Check if Psafe_mode_active is set in PMSR. */
-next:
if (pmsr & PMSR_PSAFE_ENABLE) {
throttled = true;
pr_info("Pstate set to safe frequency\n");
@@ -358,7 +377,7 @@ next:

if (throttled) {
pr_info("PMSR = %16lx\n", pmsr);
- pr_crit("CPU Frequency could be throttled\n");
+ pr_warn("CPU Frequency could be throttled\n");
}
}

@@ -449,15 +468,6 @@ void powernv_cpufreq_work_fn(struct work_struct *work)
}
}

-static char throttle_reason[][30] = {
- "No throttling",
- "Power Cap",
- "Processor Over Temperature",
- "Power Supply Failure",
- "Over Current",
- "OCC Reset"
- };
-
static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
unsigned long msg_type, void *_msg)
{
@@ -483,7 +493,7 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
*/
if (!throttled) {
throttled = true;
- pr_crit("CPU frequency is throttled for duration\n");
+ pr_warn("CPU frequency is throttled for duration\n");
}

break;
@@ -507,23 +517,18 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
return 0;
}

- if (omsg.throttle_status &&
+ for (i = 0; i < nr_chips; i++)
+ if (chips[i].id == omsg.chip)
+ break;
+
+ if (omsg.throttle_status >= 0 &&
omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS)
- pr_info("OCC: Chip %u Pmax reduced due to %s\n",
- (unsigned int)omsg.chip,
- throttle_reason[omsg.throttle_status]);
- else if (!omsg.throttle_status)
- pr_info("OCC: Chip %u %s\n", (unsigned int)omsg.chip,
- throttle_reason[omsg.throttle_status]);
- else
- return 0;
+ chips[i].throt_reason = omsg.throttle_status;

- for (i = 0; i < nr_chips; i++)
- if (chips[i].id == omsg.chip) {
- if (!omsg.throttle_status)
- chips[i].restore = true;
- schedule_work(&chips[i].throttle);
- }
+ if (!omsg.throttle_status)
+ chips[i].restore = true;
+
+ schedule_work(&chips[i].throttle);
}
return 0;
}
@@ -569,16 +574,14 @@ static int init_chip_info(void)
}
}

- chips = kmalloc_array(nr_chips, sizeof(struct chip), GFP_KERNEL);
+ chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
if (!chips)
return -ENOMEM;

for (i = 0; i < nr_chips; i++) {
chips[i].id = chip[i];
- chips[i].throttled = false;
cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
- chips[i].restore = false;
}

return 0;
--
1.9.1