From 0c608dad2a771c0a11b6d12148d1a8b975e015d4 Mon Sep 17 00:00:00 2001 From: Aubrey Li Date: Thu, 6 Jun 2019 09:22:35 +0800 Subject: x86/process: Add AVX-512 usage elapsed time to /proc/pid/arch_status AVX-512 components usage can result in turbo frequency drop. So it's useful to expose AVX-512 usage elapsed time as a heuristic hint for user space job schedulers to cluster the AVX-512 using tasks together. Examples: $ 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 tsks AVX512 usage was detected when the task was scheduled out. $ cat /proc/tid/arch_status | grep AVX512 AVX512_elapsed_ms: -1 '-1' indicates that no AVX512 usage was recorded for this task. The time exposed is not necessarily accurate when the arch_status file is read as the AVX512 usage is only evaluated when a task is scheduled out. Accurate usage information can be obtained with performance counters. [ tglx: Massaged changelog ] Signed-off-by: Aubrey Li Signed-off-by: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: peterz@infradead.org Cc: hpa@zytor.com Cc: ak@linux.intel.com Cc: tim.c.chen@linux.intel.com Cc: dave.hansen@intel.com Cc: arjan@linux.intel.com Cc: adobriyan@gmail.com Cc: aubrey.li@intel.com Cc: linux-api@vger.kernel.org Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Andi Kleen Cc: Tim Chen Cc: Dave Hansen Cc: Arjan van de Ven Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Linux API Link: https://lkml.kernel.org/r/20190606012236.9391-2-aubrey.li@linux.intel.com --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/Kconfig') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2bbbd4d1ba31..8a49b4b03f6b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -217,6 +217,7 @@ config X86 select USER_STACKTRACE_SUPPORT select VIRT_TO_BUS select X86_FEATURE_NAMES if PROC_FS + select PROC_PID_ARCH_STATUS if PROC_FS config INSTRUCTION_DECODER def_bool y -- cgit 1.4.1