[patch 05/11] perf_event_open.2: aux_{head,tail,offset,size} support

* [patch 05/11] perf_event_open.2: aux_{head,tail,offset,size} support
@ 2015-07-23 17:12 ` Vince Weaver
  0 siblings, 0 replies; 3+ messages in thread
From: Vince Weaver @ 2015-07-23 17:12 UTC (permalink / raw)
  To: Michael Kerrisk (man-pages)
  Cc: linux-man, linux-kernel, Peter Zijlstra, Ingo Molnar,
	Arnaldo Carvalho de Melo, Stephane Eranian, Alexander Shishkin,
	Borislav Petkov, Frederic Weisbecker, H. Peter Anvin, Kaixu Xia,
	Linus Torvalds, Mike Galbraith, Robert Richter, Thomas Gleixner,
	adrian.hunter, kan.liang, markus.t.metzger, mathieu.poirier,
	Vince Weaver


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

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

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

	Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
	Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
	Cc: Borislav Petkov <bp@alien8.de>
	Cc: Frederic Weisbecker <fweisbec@gmail.com>
	Cc: H. Peter Anvin <hpa@zytor.com>
	Cc: Kaixu Xia <kaixu.xia@linaro.org>
	Cc: Linus Torvalds <torvalds@linux-foundation.org>
	Cc: Mike Galbraith <efault@gmx.de>
	Cc: Paul Mackerras <paulus@samba.org>
	Cc: Robert Richter <rric@kernel.org>
	Cc: Stephane Eranian <eranian@google.com>
	Cc: Thomas Gleixner <tglx@linutronix.de>
	Cc: acme@infradead.org
	Cc: adrian.hunter@intel.com
	Cc: kan.liang@intel.com
	Cc: markus.t.metzger@intel.com
	Cc: mathieu.poirier@linaro.org
	Link: http://lkml.kernel.org/r/1421237903-181015-3-git-send-email-alexander.shishkin@linux.intel.com
	Signed-off-by: Ingo Molnar <mingo@kernel.org>



Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index a3bebaa..bd6c4c9 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1416,6 +1416,10 @@ struct perf_event_mmap_page {
     __u64 data_tail;         /* user-space written tail */
     __u64 data_offset;       /* where the buffer starts */
     __u64 data_size;         /* data buffer size */
+    __u64 aux_head;
+    __u64 aux_tail;
+    __u64 aux_offset;
+    __u64 aux_size;
 
 }
 .fi
@@ -1643,6 +1647,34 @@ where perf sample data begins.
 .\" commit e8c6deac69629c0cb97c3d3272f8631ef17f8f0f
 Contains the size of the perf sample region within
 the mmap buffer.
+.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, and the size
+must be a power of two.
+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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