> -----Original Message-----
> From: David E. Box [mailto:david.e....@linux.intel.com]
> Sent: Wednesday, April 30, 2014 4:03 AM
> To: david.e....@linux.intel.com; jacob.jun....@linux.intel.com; linux-
> p...@vger.kernel.org; Wysocki, Rafael J; linux-kernel@vger.kernel.org;
> h...@linux.intel.com
> Cc: a...@linux.intel.com; R, Durgadoss; Accardi, Kristen C
> Subject: [PATCH v2 1/4] powercap/rapl: further relax energy counter checks
>
> From: Jacob Pan <jacob.jun....@linux.intel.com>
>
> Energy counters may roll slowly for some RAPL domains, checking all
> of them can be time consuming and takes unpredictable amount of time.
> Therefore, we relax the sanity check by only checking availability of the
> MSRs and non-zero value of the energy status counters. It has been shown
> sufficient for all the platforms tested to filter out inactive domains.
>
Acked-by: Durgadoss R <durgados...@intel.com>
Thanks,
Durga
> Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
> ---
> drivers/powercap/intel_rapl.c | 29 +++++++++--------------------
> 1 file changed, 9 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
> index d9a0770..1c987d2 100644
> --- a/drivers/powercap/intel_rapl.c
> +++ b/drivers/powercap/intel_rapl.c
> @@ -1124,8 +1124,7 @@ err_cleanup_package:
> static int rapl_check_domain(int cpu, int domain)
> {
> unsigned msr;
> - u64 val1, val2 = 0;
> - int retry = 0;
> + u64 val = 0;
>
> switch (domain) {
> case RAPL_DOMAIN_PACKAGE:
> @@ -1144,26 +1143,13 @@ static int rapl_check_domain(int cpu, int domain)
> pr_err("invalid domain id %d\n", domain);
> return -EINVAL;
> }
> - if (rdmsrl_safe_on_cpu(cpu, msr, &val1))
> - return -ENODEV;
> -
> - /* PP1/uncore/graphics domain may not be active at the time of
> - * driver loading. So skip further checks.
> + /* make sure domain counters are available and contains non-zero
> + * values, otherwise skip it.
> */
> - if (domain == RAPL_DOMAIN_PP1)
> - return 0;
> - /* energy counters roll slowly on some domains */
> - while (++retry < 10) {
> - usleep_range(10000, 15000);
> - rdmsrl_safe_on_cpu(cpu, msr, &val2);
> - if ((val1 & ENERGY_STATUS_MASK) != (val2 &
> ENERGY_STATUS_MASK))
> - return 0;
> - }
> - /* if energy counter does not change, report as bad domain */
> - pr_info("domain %s energy ctr %llu:%llu not working, skip\n",
> - rapl_domain_names[domain], val1, val2);
> + if (rdmsrl_safe_on_cpu(cpu, msr, &val) || !val)
> + return -ENODEV;
>
> - return -ENODEV;
> + return 0;
> }
>
> /* Detect active and valid domains for the given CPU, caller must
> @@ -1180,6 +1166,9 @@ static int rapl_detect_domains(struct rapl_package *rp,
> int cpu)
> /* use physical package id to read counters */
> if (!rapl_check_domain(cpu, i))
> rp->domain_map |= 1 << i;
> + else
> + pr_warn("RAPL domain %s detection failed\n",
> + rapl_domain_names[i]);
> }
> rp->nr_domains = bitmap_weight(&rp->domain_map,
> RAPL_DOMAIN_MAX);
> if (!rp->nr_domains) {
> --
> 1.7.10.4
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