linux-kernel - [patch 05/10] perf_event_open.2: aux

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Message-ID: <alpine.DEB.2.11.1504161414590.15181@vincent-weaver-1.umelst.maine.edu>
Date:	Thu, 16 Apr 2015 14:15:52 -0400 (EDT)
From:	Vince Weaver <vincent.weaver@...ne.edu>
To:	"Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>
cc:	linux-man@...r.kernel.org, linux-kernel@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Stephane Eranian <eranian@...gle.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Borislav Petkov <bp@...en8.de>,
	Frederic Weisbecker <fweisbec@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>, Kaixu Xia <kaixu.xia@...aro.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Mike Galbraith <efault@....de>,
	Robert Richter <rric@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>, adrian.hunter@...el.com,
	kan.liang@...el.com, markus.t.metzger@...el.com,
	mathieu.poirier@...aro.org
Subject: [patch 05/10] perf_event_open.2: aux_{head,tail,offset,size}
 support


This manpage patch relates to the addition of the AUX mmap region
as added in the following commit:

	commit 45bfb2e50471abbbfd83d40d28c986078b0d24ff
	Author: Peter Zijlstra <peterz@...radead.org>

	perf: Add AUX area to ring buffer for raw data streams

	Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
	Acked-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
	Cc: Borislav Petkov <bp@...en8.de>
	Cc: Frederic Weisbecker <fweisbec@...il.com>
	Cc: H. Peter Anvin <hpa@...or.com>
	Cc: Kaixu Xia <kaixu.xia@...aro.org>
	Cc: Linus Torvalds <torvalds@...ux-foundation.org>
	Cc: Mike Galbraith <efault@....de>
	Cc: Paul Mackerras <paulus@...ba.org>
	Cc: Robert Richter <rric@...nel.org>
	Cc: Stephane Eranian <eranian@...gle.com>
	Cc: Thomas Gleixner <tglx@...utronix.de>
	Cc: acme@...radead.org
	Cc: adrian.hunter@...el.com
	Cc: kan.liang@...el.com
	Cc: markus.t.metzger@...el.com
	Cc: mathieu.poirier@...aro.org
	Link: http://lkml.kernel.org/r/1421237903-181015-3-git-send-email-alexander.shishkin@linux.intel.com
	Signed-off-by: Ingo Molnar <mingo@...nel.org>


Signed-off-by: Vince Weaver <vincent.weaver@...ne.edu>
 
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 01ee579..28348f9 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1348,6 +1348,10 @@ struct perf_event_mmap_page {
     __u64 __reserved[120];   /* Pad to 1k */
     __u64 data_head;         /* head in the data section */
     __u64 data_tail;         /* user-space written tail */
+    __u64   aux_head;
+    __u64   aux_tail;
+    __u64   aux_offset;
+    __u64   aux_size;
 }
 .fi
 .in
@@ -1564,6 +1568,33 @@ the
 .I data_tail
 value should be written by user space to reflect the last read data.
 In this case, the kernel will not overwrite unread data.
+.TP
+.IR aux_head ", " aux_tail ", " aux_offset ", " aux_size " (since Linux 4.1)
+.\" commit 45bfb2e50471abbbfd83d40d28c986078b0d24ff
+The AUX region allows mmaping a separate sample buffer for high
+bandwidth data streams (separate from the main perf sample buffer).
+An example of a high bandwidth stream is instruction tracing support,
+as is found in newer Intel processors.
+
+To set up an AUX area, first
+.I aux_offset
+needs to be set with an offset greater than
+.IR data_offset + data_size
+and
+.I aux_size
+needs to be set to the desired buffer size.
+The desired offset and size must be page aligned.
+These values are then passed to mmap in order to map the AUX buffer.
+Pages in the AUX buffer are included as part of the user mlock
+rlimit as well as the
+.I perf_event_mlock_kb
+allowance.
+
+The
+.IR aux_head " and " aux_tail
+ring buffer pointers have the same behavior and ordering
+rules as the previous described
+.IR data_head " and " data_tail .
 .PP
 The following 2^n ring-buffer pages have the layout described below.
 
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