{"id":2235049,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2235049/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260508131647.43868-14-frederic@kernel.org/","project":{"id":2,"url":"http://patchwork.ozlabs.org/api/1.2/projects/2/?format=json","name":"Linux PPC development","link_name":"linuxppc-dev","list_id":"linuxppc-dev.lists.ozlabs.org","list_email":"linuxppc-dev@lists.ozlabs.org","web_url":"https://github.com/linuxppc/wiki/wiki","scm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git","webscm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/","list_archive_url":"https://lore.kernel.org/linuxppc-dev/","list_archive_url_format":"https://lore.kernel.org/linuxppc-dev/{}/","commit_url_format":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}"},"msgid":"<20260508131647.43868-14-frederic@kernel.org>","list_archive_url":"https://lore.kernel.org/linuxppc-dev/20260508131647.43868-14-frederic@kernel.org/","date":"2026-05-08T13:16:45","name":"[13/15] sched/cputime: Provide get_cpu_[idle|iowait]_time_us() off-case","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"ab21c1efa445800c9f634cf844bd0730c3a0d412","submitter":{"id":79411,"url":"http://patchwork.ozlabs.org/api/1.2/people/79411/?format=json","name":"Frederic Weisbecker","email":"frederic@kernel.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260508131647.43868-14-frederic@kernel.org/mbox/","series":[{"id":503389,"url":"http://patchwork.ozlabs.org/api/1.2/series/503389/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=503389","date":"2026-05-08T13:16:32","name":"tick/sched: Refactor idle cputime accounting","version":4,"mbox":"http://patchwork.ozlabs.org/series/503389/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2235049/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2235049/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linuxppc-dev@lists.ozlabs.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=pC7lVjxq;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=112.213.38.117; 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lists.ozlabs.org;\n dmarc=pass (p=quarantine dis=none) header.from=kernel.org;\n dkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=pC7lVjxq; dkim-atps=neutral;\n spf=pass (client-ip=2600:3c04:e001:324:0:1991:8:25;\n helo=tor.source.kernel.org; envelope-from=frederic@kernel.org;\n receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1778246335;\n\tbh=hXs18NJo22xkFsprdONWIHdxUtUkDl4cfFzzNgNwNGM=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=pC7lVjxqNLRLdL/yZEx87pMBKsRgg1BBrueRkNfuR1JQWrR1QGTqH193si0q7sge6\n\t 7dxCbeAvLLLCPvT4DoeWDL6YIhyVrfDbi7foikJJb2MoQ89M9D5v8GSD4Dn/Z5E9GF\n\t Fv2mZ61cg7vq01cDiBnqhg9p8eAHv6oG0109Kpdsd0A4pcu+o/v1u/9k7GYrYwpuOT\n\t /uM6EY6hzViGh3Nyp6jNlHKUcMlX80UHQ9iu89joguve2slA2YPe9l8VLM14ZuX1MP\n\t XwgkBf4Tqjv73yQU1Zn3QtALvZALUFUrizKh9xNxhw8nLbXc8JvDGvMMjItHTfPpIR\n\t MHN8es6mrmxTg==","From":"Frederic Weisbecker ","To":"LKML ","Cc":"Frederic Weisbecker ,\n\t\"Christophe Leroy (CS GROUP)\" ,\n\t\"Rafael J. Wysocki\" ,\n\tAlexander Gordeev ,\n\tAnna-Maria Behnsen ,\n\tBen Segall , Boqun Feng ,\n\tChristian Borntraeger ,\n\tDietmar Eggemann ,\n\tHeiko Carstens , Ingo Molnar ,\n\tIngo Molnar , Jan Kiszka ,\n\tJoel Fernandes ,\n\tJuri Lelli ,\n\tKieran Bingham ,\n\tMadhavan Srinivasan ,\n\tMel Gorman , Michael Ellerman ,\n\tNeeraj Upadhyay ,\n\tNicholas Piggin ,\n\t\"Paul E . McKenney\" ,\n\tPeter Zijlstra , Sashiko@lists.ozlabs.org,\n\tShrikanth Hegde ,\n\tSteven Rostedt ,\n\tSven Schnelle ,\n\tThomas Gleixner ,\n\tUladzislau Rezki ,\n\tValentin Schneider ,\n\tVasily Gorbik ,\n\tVincent Guittot ,\n\tViresh Kumar ,\n\tXin Zhao , linux-pm@vger.kernel.org,\n\tlinux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org","Subject":"[PATCH 13/15] sched/cputime: Provide get_cpu_[idle|iowait]_time_us()\n off-case","Date":"Fri, 8 May 2026 15:16:45 +0200","Message-ID":"<20260508131647.43868-14-frederic@kernel.org>","X-Mailer":"git-send-email 2.53.0","In-Reply-To":"<20260508131647.43868-1-frederic@kernel.org>","References":"<20260508131647.43868-1-frederic@kernel.org>","X-Mailing-List":"linuxppc-dev@lists.ozlabs.org","List-Id":"","List-Help":"","List-Owner":"","List-Post":"","List-Archive":",\n ","List-Subscribe":",\n ,\n ","List-Unsubscribe":"","Precedence":"list","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Spam-Status":"No, score=-0.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,\n\tDKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS\n\tautolearn=disabled version=4.0.1 OzLabs 8","X-Spam-Checker-Version":"SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org"},"content":"The last reason why get_cpu_idle/iowait_time_us() may return -1 now is\nif the config doesn't support nohz.\n\nThe ad-hoc replacement solution by cpufreq is to compute jiffies minus\nthe whole busy cputime. Although the intention should provide a coherent\nlow resolution estimation of the idle and iowait time, the\nimplementation is buggy because jiffies don't start at 0.\n\nJust provide instead a real get_cpu_[idle|iowait]_time_us() offcase.\n\nSigned-off-by: Frederic Weisbecker \nTested-by: Shrikanth Hegde \n---\n drivers/cpufreq/cpufreq.c | 29 +----------------------------\n include/linux/kernel_stat.h | 3 +++\n include/linux/tick.h | 4 ----\n kernel/sched/cputime.c | 12 +++++++++---\n 4 files changed, 13 insertions(+), 35 deletions(-)","diff":"diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c\nindex 44eb1b7e7fc1..dda0d34d3c02 100644\n--- a/drivers/cpufreq/cpufreq.c\n+++ b/drivers/cpufreq/cpufreq.c\n@@ -130,38 +130,11 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)\n }\n EXPORT_SYMBOL_GPL(get_governor_parent_kobj);\n \n-static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)\n-{\n-\tstruct kernel_cpustat kcpustat;\n-\tu64 cur_wall_time;\n-\tu64 idle_time;\n-\tu64 busy_time;\n-\n-\tcur_wall_time = jiffies64_to_nsecs(get_jiffies_64());\n-\n-\tkcpustat_cpu_fetch(&kcpustat, cpu);\n-\n-\tbusy_time = kcpustat.cpustat[CPUTIME_USER];\n-\tbusy_time += kcpustat.cpustat[CPUTIME_SYSTEM];\n-\tbusy_time += kcpustat.cpustat[CPUTIME_IRQ];\n-\tbusy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];\n-\tbusy_time += kcpustat.cpustat[CPUTIME_STEAL];\n-\tbusy_time += kcpustat.cpustat[CPUTIME_NICE];\n-\n-\tidle_time = cur_wall_time - busy_time;\n-\tif (wall)\n-\t\t*wall = div_u64(cur_wall_time, NSEC_PER_USEC);\n-\n-\treturn div_u64(idle_time, NSEC_PER_USEC);\n-}\n-\n u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)\n {\n \tu64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);\n \n-\tif (idle_time == -1ULL)\n-\t\treturn get_cpu_idle_time_jiffy(cpu, wall);\n-\telse if (!io_busy)\n+\tif (!io_busy)\n \t\tidle_time += get_cpu_iowait_time_us(cpu, wall);\n \n \treturn idle_time;\ndiff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h\nindex 3680519d7b2c..512104b0ff49 100644\n--- a/include/linux/kernel_stat.h\n+++ b/include/linux/kernel_stat.h\n@@ -133,6 +133,9 @@ static inline bool kcpustat_idle_dyntick(void)\n }\n #endif /* CONFIG_NO_HZ_COMMON */\n \n+extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);\n+extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);\n+\n /* Fetch cputime values when vtime is disabled on a CPU */\n static inline u64 kcpustat_field_default(enum cpu_usage_stat usage, int cpu)\n {\ndiff --git a/include/linux/tick.h b/include/linux/tick.h\nindex 738007d6f577..1cf4651f09ad 100644\n--- a/include/linux/tick.h\n+++ b/include/linux/tick.h\n@@ -139,8 +139,6 @@ extern bool tick_nohz_idle_got_tick(void);\n extern ktime_t tick_nohz_get_next_hrtimer(void);\n extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next);\n extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu);\n-extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);\n-extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);\n #else /* !CONFIG_NO_HZ_COMMON */\n #define tick_nohz_enabled (0)\n static inline bool tick_nohz_is_active(void) { return false; }\n@@ -162,8 +160,6 @@ static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)\n \t*delta_next = TICK_NSEC;\n \treturn *delta_next;\n }\n-static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }\n-static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }\n #endif /* !CONFIG_NO_HZ_COMMON */\n \n /*\ndiff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c\nindex c91fd67f93ea..335d2c127763 100644\n--- a/kernel/sched/cputime.c\n+++ b/kernel/sched/cputime.c\n@@ -522,6 +522,13 @@ u64 kcpustat_field_iowait(int cpu)\n \t\t\t\t nr_iowait_cpu(cpu), ktime_get());\n }\n EXPORT_SYMBOL_GPL(kcpustat_field_iowait);\n+#else\n+static u64 kcpustat_field_dyntick(int cpu, enum cpu_usage_stat idx,\n+\t\t\t\t bool compute_delta, ktime_t now)\n+{\n+\treturn kcpustat_cpu(cpu).cpustat[idx];\n+}\n+#endif /* CONFIG_NO_HZ_COMMON */\n \n static u64 get_cpu_sleep_time_us(int cpu, enum cpu_usage_stat idx,\n \t\t\t\t bool compute_delta, u64 *last_update_time)\n@@ -557,7 +564,7 @@ static u64 get_cpu_sleep_time_us(int cpu, enum cpu_usage_stat idx,\n * This time is measured via accounting rather than sampling,\n * and is as accurate as ktime_get() is.\n *\n- * Return: -1 if generic vtime is enabled, else total idle time of the @cpu\n+ * Return: total idle time of the @cpu\n */\n u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)\n {\n@@ -581,7 +588,7 @@ EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);\n * This time is measured via accounting rather than sampling,\n * and is as accurate as ktime_get() is.\n *\n- * Return: -1 if generic vtime is enabled, else total iowait time of @cpu\n+ * Return: total iowait time of @cpu\n */\n u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)\n {\n@@ -589,7 +596,6 @@ u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)\n \t\t\t\t nr_iowait_cpu(cpu), last_update_time);\n }\n EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);\n-#endif /* CONFIG_NO_HZ_COMMON */\n \n /*\n * Use precise platform statistics if available:\n","prefixes":["13/15"]}