Hi Chris,
On Wed, Mar 25, 2020 at 08:10:56AM +0000, Chris Wilson wrote:
> Measure and compare the energy consumed, as reported by the rapl MSR,
> by the GPU while in RC0 and RC6 states. Throw an error if RC6 does not
> at least halve the energy consumption of RC0, as this more than likely
> means we failed to enter RC0 correctly.
>
> If we can't measure the energy draw with the MSR, then it will report 0
> for both measurements. Since the measurement works on all gen6+, this seems
> worth flagging as an error.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
> Cc: Andi Shyti <andi.shyti@xxxxxxxxx>
would be nice to have a revision history, given that I got quite
some versions of this patch.
> +static u64 energy_uJ(struct intel_rc6 *rc6)
> +{
> + unsigned long long power;
> + u32 units;
> +
> + if (rdmsrl_safe(MSR_RAPL_POWER_UNIT, &power))
> + return 0;
> +
> + units = (power & 0x1f00) >> 8;
> +
> + if (rdmsrl_safe(MSR_PP1_ENERGY_STATUS, &power))
> + return 0;
> +
> + return (1000000 * power) >> units; /* convert to uJ */
> +}
shall we put this in a library?
> res[0] = rc6_residency(rc6);
> + dt = ktime_get();
> + rc0_power = energy_uJ(rc6);
> msleep(250);
> + rc0_power = energy_uJ(rc6) - rc0_power;
> + dt = ktime_sub(ktime_get(), dt);
> res[1] = rc6_residency(rc6);
> if ((res[1] - res[0]) >> 10) {
> pr_err("RC6 residency increased by %lldus while disabled for 250ms!\n",
> @@ -63,13 +85,23 @@ int live_rc6_manual(void *arg)
> goto out_unlock;
> }
>
> + rc0_power = div64_u64(NSEC_PER_SEC * rc0_power, ktime_to_ns(dt));
> + if (!rc0_power) {
is this likely to happen?
> res[0] = rc6_residency(rc6);
> + dt = ktime_get();
> + rc6_power = energy_uJ(rc6);
> msleep(100);
> + rc6_power = energy_uJ(rc6) - rc6_power;
> + dt = ktime_sub(ktime_get(), dt);
> res[1] = rc6_residency(rc6);
> -
> if (res[1] == res[0]) {
> pr_err("Did not enter RC6! RC6_STATE=%08x, RC6_CONTROL=%08x, residency=%lld\n",
> intel_uncore_read_fw(gt->uncore, GEN6_RC_STATE),
> @@ -78,6 +110,15 @@ int live_rc6_manual(void *arg)
> err = -EINVAL;
> }
>
> + 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!\n");
> + err = -EINVAL;
> + goto out_unlock;
> + }
nice,
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxx>
Thanks,
Andi
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