From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 86D661A0D35 for ; Thu, 21 Jan 2016 20:40:09 +1100 (AEDT) Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 624C91402EC for ; Thu, 21 Jan 2016 20:40:09 +1100 (AEDT) Received: from localhost by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Jan 2016 19:40:08 +1000 Received: from d23relay07.au.ibm.com (d23relay07.au.ibm.com [9.190.26.37]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id E0E392BB0055 for ; Thu, 21 Jan 2016 20:40:05 +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 u0L9dxiI32637070 for ; Thu, 21 Jan 2016 20:40:07 +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 u0L9dWNs018127 for ; Thu, 21 Jan 2016 20:39:33 +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> 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> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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); -- 1.9.3