From: Sk Anirban <sk.anir...@intel.com>

Refactor power measurement logic to store and compare energy values.
Introduce a threshold check to ensure the GPU enters RC6 properly.

v2:
  - Improved commit message (Badal)

v3:
 - Reorder threshold check (Badal)

Signed-off-by: Sk Anirban <sk.anir...@intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_rc6.c | 59 +++++++++++++++++---------
 1 file changed, 38 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_rc6.c 
b/drivers/gpu/drm/i915/gt/selftest_rc6.c
index 908483ab0bc8..5364e50be638 100644
--- a/drivers/gpu/drm/i915/gt/selftest_rc6.c
+++ b/drivers/gpu/drm/i915/gt/selftest_rc6.c
@@ -33,15 +33,20 @@ int live_rc6_manual(void *arg)
 {
        struct intel_gt *gt = arg;
        struct intel_rc6 *rc6 = &gt->rc6;
-       u64 rc0_power, rc6_power;
+       struct intel_rps *rps = &gt->rps;
        intel_wakeref_t wakeref;
+       u64 sleep_time = 1000;
+       u32 rc0_freq = 0;
+       u32 rc6_freq = 0;
+       u64 rc0_power[3];
+       u64 rc6_power[3];
        bool has_power;
+       u64 threshold;
        ktime_t dt;
        u64 res[2];
        int err = 0;
-       u32 rc0_freq = 0;
-       u32 rc6_freq = 0;
-       struct intel_rps *rps = &gt->rps;
+       u64 diff;
+
 
        /*
         * Our claim is that we can "encourage" the GPU to enter rc6 at will.
@@ -65,9 +70,9 @@ int live_rc6_manual(void *arg)
        res[0] = rc6_residency(rc6);
 
        dt = ktime_get();
-       rc0_power = librapl_energy_uJ();
-       msleep(1000);
-       rc0_power = librapl_energy_uJ() - rc0_power;
+       rc0_power[0] = librapl_energy_uJ();
+       msleep(sleep_time);
+       rc0_power[1] = librapl_energy_uJ() - rc0_power[0];
        dt = ktime_sub(ktime_get(), dt);
        res[1] = rc6_residency(rc6);
        rc0_freq = intel_rps_read_actual_frequency_fw(rps);
@@ -79,11 +84,12 @@ int live_rc6_manual(void *arg)
        }
 
        if (has_power) {
-               rc0_power = div64_u64(NSEC_PER_SEC * rc0_power,
-                                     ktime_to_ns(dt));
-               if (!rc0_power) {
+               rc0_power[2] = div64_u64(NSEC_PER_SEC * rc0_power[1],
+                                        ktime_to_ns(dt));
+
+               if (!rc0_power[2]) {
                        if (rc0_freq)
-                               pr_debug("No power measured while in RC0! GPU 
Freq: %u in RC0\n",
+                               pr_debug("No power measured while in RC0! GPU 
Freq: %uMHz in RC0\n",
                                         rc0_freq);
                        else
                                pr_err("No power and freq measured while in 
RC0\n");
@@ -98,10 +104,10 @@ int live_rc6_manual(void *arg)
        res[0] = rc6_residency(rc6);
        intel_uncore_forcewake_flush(rc6_to_uncore(rc6), FORCEWAKE_ALL);
        dt = ktime_get();
-       rc6_power = librapl_energy_uJ();
-       msleep(1000);
+       rc6_power[0] = librapl_energy_uJ();
+       msleep(sleep_time);
        rc6_freq = intel_rps_read_actual_frequency_fw(rps);
-       rc6_power = librapl_energy_uJ() - rc6_power;
+       rc6_power[1] = librapl_energy_uJ() - rc6_power[0];
        dt = ktime_sub(ktime_get(), dt);
        res[1] = rc6_residency(rc6);
        if (res[1] == res[0]) {
@@ -113,13 +119,24 @@ int live_rc6_manual(void *arg)
        }
 
        if (has_power) {
-               rc6_power = div64_u64(NSEC_PER_SEC * rc6_power,
-                                     ktime_to_ns(dt));
-               pr_info("GPU consumed %llduW in RC0 and %llduW in RC6\n",
-                       rc0_power, rc6_power);
-               if (2 * rc6_power > rc0_power) {
-                       pr_err("GPU leaked energy while in RC6! GPU Freq: %u in 
RC6 and %u in RC0\n",
-                              rc6_freq, rc0_freq);
+               rc6_power[2] = div64_u64(NSEC_PER_SEC * rc6_power[1],
+                                        ktime_to_ns(dt));
+               pr_info("GPU consumed %lluuW in RC0 and %lluuW in RC6\n",
+                       rc0_power[2], rc6_power[2]);
+
+               if (2 * rc6_power[2] > rc0_power[2]) {
+                       pr_err("GPU leaked energy while in RC6!\n"
+                              "GPU Freq: %uMHz in RC6 and %uMHz in RC0\n"
+                              "RC0 energy before & after sleep respectively: 
%lluuJ %lluuJ\n"
+                              "RC6 energy before & after sleep respectively: 
%lluuJ %lluuJ\n",
+                              rc6_freq, rc0_freq, rc0_power[0], rc0_power[1],
+                              rc6_power[0], rc6_power[1]);
+
+                       diff = res[1] - res[0];
+                       threshold = (9 * NSEC_PER_MSEC * sleep_time) / 10;
+                       if (diff < threshold)
+                               pr_err("Did not enter RC6 properly, RC6 start 
residency=%lluns, RC6 end residency=%lluns\n",
+                                      res[0], res[1]);
                        err = -EINVAL;
                        goto out_unlock;
                }
-- 
2.34.1

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