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 891C2C282D7 for ; Tue, 12 Feb 2019 02:19:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 635DF21B18 for ; Tue, 12 Feb 2019 02:19:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727960AbfBLCT0 (ORCPT ); Mon, 11 Feb 2019 21:19:26 -0500 Received: from mga03.intel.com ([134.134.136.65]:25316 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727265AbfBLCTX (ORCPT ); Mon, 11 Feb 2019 21:19:23 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Feb 2019 18:19:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,361,1544515200"; d="scan'208";a="123748588" Received: from aubrey-skl.sh.intel.com ([10.239.53.19]) by fmsmga008.fm.intel.com with ESMTP; 11 Feb 2019 18:19:21 -0800 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, aubrey.li@intel.com, linux-kernel@vger.kernel.org, Aubrey Li Subject: [PATCH v9 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time Date: Tue, 12 Feb 2019 02:59:30 +0800 Message-Id: <20190211185931.4386-2-aubrey.li@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190211185931.4386-1-aubrey.li@intel.com> References: <20190211185931.4386-1-aubrey.li@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. Example: $ cat /proc/pid/status | grep AVX512_elapsed_ms AVX512_elapsed_ms: 1020 The number '1020' denotes 1020 millisecond elapsed since last time context switch the off-CPU task using AVX-512 components, thus the task could cause core frequency drop. Or: $ cat /proc/pid/status | grep AVX512_elapsed_ms AVX512_elapsed_ms: -1 The number '-1' indicates the task didn't use AVX-512 components before thus 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: Peter Zijlstra Cc: Andi Kleen Cc: Tim Chen Cc: Dave Hansen Cc: Arjan van de Ven --- arch/x86/include/asm/processor.h | 2 ++ arch/x86/kernel/fpu/xstate.c | 41 ++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index d53c54b842da..60ee932070fe 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -996,5 +996,7 @@ enum l1tf_mitigations { }; extern enum l1tf_mitigations l1tf_mitigation; +/* Add support for architecture specific output in /proc/pid/status */ +extern void arch_proc_pid_status(struct seq_file *m, struct task_struct *task); #endif /* _ASM_X86_PROCESSOR_H */ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 87a57b7642d3..dfd7cf847bc3 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 @@ -1245,3 +1246,43 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) return 0; } + +/* + * Report the amount of time elapsed in millisecond since last AVX512 + * use in the task. + */ +void avx512_status(struct seq_file *m, struct task_struct *task) +{ + unsigned long timestamp = 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 arch_proc_pid_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); +} -- 2.17.1