Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752919AbbDAJpG (ORCPT ); Wed, 1 Apr 2015 05:45:06 -0400 Received: from e28smtp03.in.ibm.com ([122.248.162.3]:55964 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751433AbbDAJpB (ORCPT ); Wed, 1 Apr 2015 05:45:01 -0400 Message-ID: <551BBE11.6010309@linux.vnet.ibm.com> Date: Wed, 01 Apr 2015 15:14:49 +0530 From: Shilpasri G Bhat User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" , Viresh Kumar CC: "linux-pm@vger.kernel.org" , Linux Kernel Mailing List Subject: Re: [PATCH v3] cpufreq: powernv: Report cpu frequency throttling References: <1427441523-5189-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> <2339245.XXG4qaq6pt@vostro.rjw.lan> In-Reply-To: <2339245.XXG4qaq6pt@vostro.rjw.lan> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15040109-0009-0000-0000-000004A8D5B3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5070 Lines: 123 Hi Rafael, On 03/31/2015 12:45 AM, Rafael J. Wysocki wrote: > On Friday, March 27, 2015 01:10:46 PM Viresh Kumar wrote: >> On 27 March 2015 at 13:02, Shilpasri G Bhat >> wrote: >>> The power and thermal safety of the system is taken care by an >>> On-Chip-Controller (OCC) which is real-time subsystem embedded within >>> the POWER8 processor. OCC continuously monitors the memory and core >>> temperature, the total system power, state of power supply and fan. >>> >>> The cpu frequency can be throttled by OCC for the following reasons: >>> 1)If a processor crosses its power and temperature limit then OCC will >>> lower its Pmax to reduce the frequency and voltage. >>> 2)If OCC crashes then the system is forced to Psafe frequency. >>> 3)If OCC fails to recover then the kernel is not allowed to do any >>> further frequency changes and the chip will remain in Psafe. >>> >>> The user can see a drop in performance when frequency is throttled and >>> is unaware of throttling. So detect and report such a condition so >>> that user can check the OCC status to reboot the system or check for >>> power supply or fan failures. >>> >>> The current status of the core is read from Power Management Status >>> Register(PMSR) to check if any of the throttling condition is occurred >>> and the appropriate throttling message is reported. >>> >>> Signed-off-by: Shilpasri G Bhat >>> --- >>> Changes from V2: >>> -Changed commit log to add more details. >>> -Fixed multi-line comment to proper format >>> >>> Changes from V1: Removed unused value of PMCR register >>> >>> drivers/cpufreq/powernv-cpufreq.c | 40 ++++++++++++++++++++++++++++++++++++++- >>> 1 file changed, 39 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c >>> index 2dfd4fd..0eb89a9 100644 >>> --- a/drivers/cpufreq/powernv-cpufreq.c >>> +++ b/drivers/cpufreq/powernv-cpufreq.c >>> @@ -36,7 +36,7 @@ >>> #define POWERNV_MAX_PSTATES 256 >>> >>> static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1]; >>> -static bool rebooting; >>> +static bool rebooting, throttled; >>> >>> /* >>> * Note: The set of pstates consists of contiguous integers, the >>> @@ -294,6 +294,41 @@ static inline unsigned int get_nominal_index(void) >>> return powernv_pstate_info.max - powernv_pstate_info.nominal; >>> } >>> >>> +static void powernv_cpufreq_throttle_check(unsigned int cpu) >>> +{ >>> + unsigned long pmsr; >>> + int pmsr_pmax, pmsr_lp; >>> + >>> + pmsr = get_pmspr(SPRN_PMSR); >>> + >>> + /* Check for Pmax Capping */ >>> + pmsr_pmax = (s8)((pmsr >> 32) & 0xFF); >>> + if (pmsr_pmax != powernv_pstate_info.max) { >>> + throttled = true; >>> + pr_warn("Cpu %d Pmax is reduced to %d\n", cpu, pmsr_pmax); >>> + } >>> + >>> + /* >>> + * Check for Psafe by reading LocalPstate >>> + * or check if Psafe_mode_active- 34th bit is set in PMSR. >>> + */ >>> + pmsr_lp = (s8)((pmsr >> 48) & 0xFF); >>> + if ((pmsr_lp < powernv_pstate_info.min) || ((pmsr >> 30) & 1)) { >>> + throttled = true; >>> + pr_warn("Cpu %d in Psafe %d PMSR[34]=%lx\n", cpu, >>> + pmsr_lp, ((pmsr >> 30) & 1)); >>> + } >>> + >>> + /* Check if SPR_EM_DISABLED- 33rd bit is set in PMSR */ >>> + if ((pmsr >> 31) & 1) { >>> + throttled = true; >>> + pr_warn("Frequency management disabled cpu %d PMSR[33]=%lx\n", >>> + cpu, ((pmsr >> 31) & 1)); >>> + } >>> + if (throttled) >>> + pr_warn("Cpu Frequency is throttled\n"); >>> +} >>> + >>> /* >>> * powernv_cpufreq_target_index: Sets the frequency corresponding to >>> * the cpufreq table entry indexed by new_index on the cpus in the >>> @@ -307,6 +342,9 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy, >>> if (unlikely(rebooting) && new_index != get_nominal_index()) >>> return 0; >>> >>> + if (!throttled) >>> + powernv_cpufreq_throttle_check(smp_processor_id()); >>> + >>> freq_data.pstate_id = powernv_freqs[new_index].driver_data; >> >> Acked-by: Viresh Kumar > > Queued up for 4.1, thanks! > > Kindly revert this patch. This patch requires additional cosmetic changes for better readability and maintenance, without any change in functionality. I would have wanted to post the diff with the additional changes in this patch but it touches almost the whole thing, so I will post out v4 version of this patch with all the changes. Apologies for the inconvenience. Thanks and Regards, Shilpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/