From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4598DC282E3 for ; Mon, 22 Apr 2019 01:57:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21C5D2075A for ; Mon, 22 Apr 2019 01:57:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726405AbfDVB5W (ORCPT ); Sun, 21 Apr 2019 21:57:22 -0400 Received: from mga02.intel.com ([134.134.136.20]:48592 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbfDVB5V (ORCPT ); Sun, 21 Apr 2019 21:57:21 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Apr 2019 18:57:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,380,1549958400"; d="scan'208";a="151240128" Received: from aubrey-skl.sh.intel.com ([10.239.53.6]) by FMSMGA003.fm.intel.com with ESMTP; 21 Apr 2019 18:57:18 -0700 From: Aubrey Li To: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, hpa@zytor.com Cc: ak@linux.intel.com, tim.c.chen@linux.intel.com, dave.hansen@intel.com, arjan@linux.intel.com, adobriyan@gmail.com, akpm@linux-foundation.org, aubrey.li@intel.com, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Aubrey Li , Andy Lutomirski Subject: [PATCH v17 2/3] /proc/pid/arch_status: Add AVX-512 usage elapsed time Date: Mon, 22 Apr 2019 02:35:28 +0800 Message-Id: <20190421183529.9141-2-aubrey.li@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190421183529.9141-1-aubrey.li@linux.intel.com> References: <20190421183529.9141-1-aubrey.li@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org AVX-512 components use could cause core turbo frequency drop. So it's useful to expose AVX-512 usage elapsed time as a heuristic hint for the user space job scheduler to cluster the AVX-512 using tasks together. Tensorflow example: $ while [ 1 ]; do cat /proc/tid/arch_status | grep AVX512; sleep 1; done AVX512_elapsed_ms: 4 AVX512_elapsed_ms: 8 AVX512_elapsed_ms: 4 This means that 4 milliseconds have elapsed since the AVX512 usage of tensorflow task was detected when the task was scheduled out. Or: $ cat /proc/tid/arch_status | grep AVX512 AVX512_elapsed_ms: -1 The number '-1' indicates that no AVX512 usage recorded before thus the task unlikely has frequency drop issue. User space tools may want to further check by: $ perf stat --pid -e core_power.lvl2_turbo_license -- sleep 1 Performance counter stats for process id '3558': 3,251,565,961 core_power.lvl2_turbo_license 1.004031387 seconds time elapsed Non-zero counter value confirms that the task causes frequency drop. Signed-off-by: Aubrey Li Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Andi Kleen Cc: Tim Chen Cc: Dave Hansen Cc: Arjan van de Ven Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Andy Lutomirski Cc: Linux API --- arch/x86/include/asm/processor.h | 6 +++++ arch/x86/kernel/fpu/xstate.c | 43 ++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 2bb3a648fc12..0728848473a2 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -991,4 +991,10 @@ enum l1tf_mitigations { extern enum l1tf_mitigations l1tf_mitigation; +#ifdef CONFIG_PROC_PID_ARCH_STATUS +/* Add support for task architecture specific output in /proc/pid/arch_status */ +void task_arch_status(struct seq_file *m, struct task_struct *task); +#define task_arch_status task_arch_status +#endif /* CONFIG_PROC_PID_ARCH_STATUS */ + #endif /* _ASM_X86_PROCESSOR_H */ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index d7432c2b1051..a0dda11ab72e 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -1243,3 +1244,45 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) return 0; } + +#ifdef CONFIG_PROC_PID_ARCH_STATUS +/* + * Report the amount of time elapsed in millisecond since last AVX512 + * use in the task. + */ +static void avx512_status(struct seq_file *m, struct task_struct *task) +{ + unsigned long timestamp = READ_ONCE(task->thread.fpu.avx512_timestamp); + long delta; + + if (!timestamp) { + /* + * Report -1 if no AVX512 usage + */ + delta = -1; + } else { + delta = (long)(jiffies - timestamp); + /* + * Cap to LONG_MAX if time difference > LONG_MAX + */ + if (delta < 0) + delta = LONG_MAX; + delta = jiffies_to_msecs(delta); + } + + seq_put_decimal_ll(m, "AVX512_elapsed_ms:\t", delta); + seq_putc(m, '\n'); +} + +/* + * Report architecture specific information + */ +void task_arch_status(struct seq_file *m, struct task_struct *task) +{ + /* + * Report AVX512 state if the processor and build option supported. + */ + if (cpu_feature_enabled(X86_FEATURE_AVX512F)) + avx512_status(m, task); +} +#endif /* CONFIG_PROC_PID_ARCH_STATUS */ -- 2.17.1