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Violators will be prosecuted; Thu, 21 Jan 2016 19:40:06 +1000 X-IBM-Helo: d23dlp03.au.ibm.com X-IBM-MailFrom: shilpa.bhat@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-pm@vger.kernel.org Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 427933578055; Thu, 21 Jan 2016 20:40:06 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u0L9dwNr16842802; Thu, 21 Jan 2016 20:40:06 +1100 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u0L9dWO2018127; Thu, 21 Jan 2016 20:39:34 +1100 Received: from localhost.in.ibm.com ([9.77.193.62]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u0L9dIXs017121; Thu, 21 Jan 2016 20:39:30 +1100 From: Shilpasri G Bhat To: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Cc: rjw@rjwysocki.net, viresh.kumar@linaro.org, linux-pm@vger.kernel.org, pc@us.ibm.com, anton@samba.org, ego@linux.vnet.ibm.com, shreyas@linux.vnet.ibm.com, Shilpasri G Bhat Subject: [PATCH v5 2/5] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path Date: Thu, 21 Jan 2016 15:08:56 +0530 Message-Id: <1453369139-10203-3-git-send-email-shilpa.bhat@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1453369139-10203-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> References: <1453369139-10203-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16012109-0029-0000-0000-000043E73476 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP cpu_to_chip_id() does a DT walk through to find out the chip id by taking a contended device tree lock. This adds an unnecessary overhead in a hot path. So instead of calling cpu_to_chip_id() everytime cache the chip ids for all cores in the array 'core_to_chip_map' and use it in the hotpath. Reported-by: Anton Blanchard Signed-off-by: Shilpasri G Bhat Reviewed-by: Gautham R. Shenoy --- Changes from v4: - Taken care of Shreyas's comments to add a core_to_chip_map array to store the chip id. drivers/cpufreq/powernv-cpufreq.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 50a5b21..5ea103d 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -42,6 +42,7 @@ static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1]; static bool rebooting, throttled, occ_reset; +static unsigned int *core_to_chip_map; static struct chip { unsigned int id; @@ -312,13 +313,14 @@ static inline unsigned int get_nominal_index(void) static void powernv_cpufreq_throttle_check(void *data) { unsigned int cpu = smp_processor_id(); + unsigned int chip_id = core_to_chip_map[cpu_core_index_of_thread(cpu)]; unsigned long pmsr; int pmsr_pmax, i; pmsr = get_pmspr(SPRN_PMSR); for (i = 0; i < nr_chips; i++) - if (chips[i].id == cpu_to_chip_id(cpu)) + if (chips[i].id == chip_id) break; /* Check for Pmax Capping */ @@ -558,19 +560,29 @@ static int init_chip_info(void) unsigned int chip[256]; unsigned int cpu, i; unsigned int prev_chip_id = UINT_MAX; + cpumask_t cpu_mask; + int ret = -ENOMEM; - for_each_possible_cpu(cpu) { + cpumask_copy(&cpu_mask, cpu_possible_mask); + core_to_chip_map = kcalloc(cpu_nr_cores(), sizeof(unsigned int), + GFP_KERNEL); + if (!core_to_chip_map) + goto out; + + for_each_cpu(cpu, &cpu_mask) { unsigned int id = cpu_to_chip_id(cpu); if (prev_chip_id != id) { prev_chip_id = id; chip[nr_chips++] = id; } + core_to_chip_map[cpu_core_index_of_thread(cpu)] = id; + cpumask_andnot(&cpu_mask, &cpu_mask, cpu_sibling_mask(cpu)); } chips = kmalloc_array(nr_chips, sizeof(struct chip), GFP_KERNEL); if (!chips) - return -ENOMEM; + goto free_chip_map; for (i = 0; i < nr_chips; i++) { chips[i].id = chip[i]; @@ -581,6 +593,10 @@ static int init_chip_info(void) } return 0; +free_chip_map: + kfree(core_to_chip_map); +out: + return ret; } static int __init powernv_cpufreq_init(void) @@ -614,6 +630,8 @@ static void __exit powernv_cpufreq_exit(void) unregister_reboot_notifier(&powernv_cpufreq_reboot_nb); opal_message_notifier_unregister(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb); + kfree(chips); + kfree(core_to_chip_map); cpufreq_unregister_driver(&powernv_cpufreq_driver); } module_exit(powernv_cpufreq_exit);