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Violators will be prosecuted; Fri, 22 Jan 2016 17:20:08 +1000 X-IBM-Helo: d23dlp01.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 d23relay07.au.ibm.com (d23relay07.au.ibm.com [9.190.26.37]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 58C572CE802D; Fri, 22 Jan 2016 18:20:08 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u0M7K2bt37683372; Fri, 22 Jan 2016 18:20:10 +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 u0M7JYdf023492; Fri, 22 Jan 2016 18:19:35 +1100 Received: from localhost.in.ibm.com ([9.79.217.113]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u0M7JNsm022822; Fri, 22 Jan 2016 18:19:32 +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 v6 2/5] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path Date: Fri, 22 Jan 2016 12:49:02 +0530 Message-Id: <1453447145-17722-3-git-send-email-shilpa.bhat@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1453447145-17722-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> References: <1453447145-17722-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16012207-0033-0000-0000-000002CA7DEA 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 --- No changes from v5. 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 140c75f..6f186dc 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -43,6 +43,7 @@ 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; @@ -313,13 +314,14 @@ 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 */ @@ -559,19 +561,29 @@ 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]; @@ -582,6 +594,10 @@ 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) @@ -615,6 +631,8 @@ 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);