Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755688AbbGUPts (ORCPT ); Tue, 21 Jul 2015 11:49:48 -0400 Received: from mail-ie0-f181.google.com ([209.85.223.181]:32963 "EHLO mail-ie0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754568AbbGUPtr (ORCPT ); Tue, 21 Jul 2015 11:49:47 -0400 From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Tue, 21 Jul 2015 11:56:23 -0400 (EDT) To: Vince Weaver cc: "Michael Kerrisk (man-pages)" , linux-man@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Stephane Eranian , Jiri Olsa , cebbert.lkml@gmail.com, Linus Torvalds , andi@firstfloor.org Subject: [patch v3] perf_event_open.2: 3.19 PERF_SAMPLE_REGS_INTR support In-Reply-To: Message-ID: References: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4112 Lines: 127 Let's retry that without the accidental cut-and-paste duplication of the patch :( This manpage patch relates to the addition of PERF_SAMPLE_REGS_INTR support added in the following commit: perf_sample_regs_intr; Linux 3.19 commit 60e2364e60e86e81bc6377f49779779e6120977f Author: Stephane Eranian perf: Add ability to sample machine state on interrupt Reviewed-by: Jiri Olsa Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra (Intel) Cc: cebbert.lkml@gmail.com Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: linux-api@vger.kernel.org Link: http://lkml.kernel.org/r/1411559322-16548-2-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar The primary difference between PERF_SAMPLE_REGS_INTR and the existing PERF_SAMPLE_REGS_USER is that the new support will return kernel register values. Also if precise_ip is set higher than 0 then the PEBS register state will be returned rather than the saved interrupt state. This patch incorporates feedback from Stephane Eranian and Andi Kleen. Signed-off-by: Vince Weaver diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 index 01ee579..f6a2865 100644 --- a/man2/perf_event_open.2 +++ b/man2/perf_event_open.2 @@ -256,7 +256,7 @@ struct perf_event_attr { __u32 sample_stack_user; /* size of stack to dump on samples */ __u32 __reserved_2; /* Align to u64 */ - + __u64 sample_regs_intr; /* regs to dump on samples */ }; .fi .in @@ -350,6 +350,11 @@ and .I sample_stack_user in Linux 3.7. .\" commit 1659d129ed014b715b0b2120e6fd929bdd33ed03 +.B PERF_ATTR_SIZE_VER4 +is 104 corresponding to the addition of +.I sample_regs_intr +in Linux 3.19. +.\" commit 60e2364e60e86e81bc6377f49779779e6120977f .TP .I "config" This specifies which event you want, in conjunction with @@ -752,6 +757,24 @@ event must be measured or no values will be recorded. Also note that some perf_event measurements, such as sampled cycle counting, may cause extraneous aborts (by causing an interrupt during a transaction). +.TP +.BR PERF_SAMPLE_REGS_INTR " (since Linux 3.19)" +.\" commit 60e2364e60e86e81bc6377f49779779e6120977f +Records a subset of the current CPU register state +as specified by +.IR sample_regs_intr . +Unlike +.B PERF_SAMPLE_REGS_USER +the register values will return kernel register +state if the overflow happened while kernel +code is running. +If the CPU supports hardware sampling of +register state (i.e. PEBS on Intel x86) and +.I precise_ip +is set higher than zero then the register +values returned are those captured by +hardware at the time of the sampled +instruction's retirement. .RE .TP .IR "read_format" @@ -1855,6 +1878,9 @@ struct { u64 weight; /* if PERF_SAMPLE_WEIGHT */ u64 data_src; /* if PERF_SAMPLE_DATA_SRC */ u64 transaction;/* if PERF_SAMPLE_TRANSACTION */ + u64 abi; /* if PERF_SAMPLE_REGS_INTR */ + u64 regs[weight(mask)]; + /* if PERF_SAMPLE_REGS_INTR */ }; .fi .RS 4 @@ -2242,6 +2268,27 @@ the high 32 bits of the field by shifting right by .B PERF_TXN_ABORT_SHIFT and masking with .BR PERF_TXN_ABORT_MASK . +.TP +.IR abi ", " regs[weight(mask)] +If +.B PERF_SAMPLE_REGS_INTR +is enabled, then the user CPU registers are recorded. + +The +.I abi +field is one of +.BR PERF_SAMPLE_REGS_ABI_NONE ", " PERF_SAMPLE_REGS_ABI_32 " or " +.BR PERF_SAMPLE_REGS_ABI_64 . + +The +.I regs +field is an array of the CPU registers that were specified by +the +.I sample_regs_intr +attr field. +The number of values is the number of bits set in the +.I sample_regs_intr +bit mask. .RE .TP .B PERF_RECORD_MMAP2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/