* perf_event_open() -- improve sysfs files documentation
@ 2013-07-16 5:36 Vince Weaver
[not found] ` <alpine.DEB.2.10.1307160134570.31834-6xBS8L8d439fDsnSvq7Uq4Se7xf15W0s1dQoKJhdanU@public.gmane.org>
0 siblings, 1 reply; 2+ messages in thread
From: Vince Weaver @ 2013-07-16 5:36 UTC (permalink / raw)
To: Michael Kerrisk; +Cc: linux-man-u79uwXL29TY76Z2rM5mHXA
This improves the documentation of the various perf_event_open()
related sysfs files.
Signed-off-by: Vince Weaver <vincent.weaver-e7X0jjDqjFGHXe+LvDLADg@public.gmane.org>
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 504e801..e7ddcb2 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1926,6 +1926,7 @@ The default value is
Maximum number of pages an unprivileged user can mlock (2) .
The default is 516 (kB).
+
.RE
Files in
.I /sys/bus/event_source/devices/
@@ -1936,30 +1937,59 @@ Information on how to program these PMUs can be found under
.IR /sys/bus/event_source/devices/ .
Each subdirectory corresponds to a different PMU.
.TP
-.I /sys/bus/event_source/devices/*/type
+.IR /sys/bus/event_source/devices/*/type " (Since Linux 2.6.38)"
This contains an integer that can be used in the
.I type
field of perf_event_attr to indicate you wish to use this PMU.
.TP
-.I /sys/bus/event_source/devices/*/rdpmc
-[To be documented]
+.IR /sys/bus/event_source/devices/*/rdpmc " (Since Linux 3.4)"
+If this file is 1, then direct user-space access to the
+performance counter registers is allowed via the rdpmc instruction.
+This can be disabled by echoing 0 to the file.
.TP
-.I /sys/bus/event_source/devices/*/format/
-This sub-directory contains information on what bits in the
+.IR /sys/bus/event_source/devices/*/format/ " (Since Linux 3.4)"
+This sub-directory contains information on the architecture-specific
+sub-fields available for programming the various
.I config
-field of perf_event_attr correspond to.
-.TP
-.I /sys/bus/event_source/devices/*/events/
+fields in the perf_event_attr struct.
+
+The content of each file is the name of the config field, followed
+by a colon, followed by a series of integer bit ranges separated by
+commas.
+For example, the file
+.I event
+may contain the value
+.I config1:1,6-10,44
+which indicates that event is an attribute that occupies bits 1,6-10, and 44
+of perf_event_attr::config1.
+.TP
+.IR /sys/bus/event_source/devices/*/events/ " (Since Linux 3.4)"
This sub-directory contains files with pre-defined events.
The contents are strings describing the event settings
-expressed in terms of the fields found in the
+expressed in terms of the fields found in the previously mentioned
.I ./format/
directory.
These are not necessarily complete lists of all events supported by
a PMU, but usually a subset of events deemed useful or interesting.
+
+The content of each file is a list of attribute names
+separated by commas.
+Each entry has an optional value (either hex or decimal).
+If no value is specified than it is assumed to be a single-bit
+field with a value of 1.
+An example entry may look like this:
+.I event=0x2,inv,ldlat=3
.TP
.I /sys/bus/event_source/devices/*/uevent
-[To be documented]
+This file is the standard kernel device interface
+for injecting hotplug events.
+.TP
+.IR /sys/bus/event_source/devices/*/cpumask " (Since Linux 3.7)"
+The cpumask file contains a comma-separated list of integers that
+indicate a representative cpu number for each socket (package)
+on the motherboard.
+This is needed when setting up uncore or northbridge events, as
+those PMUs present socket-wide events.
.RE
.SH RETURN VALUE
.BR perf_event_open ()
--
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: perf_event_open() -- improve sysfs files documentation
[not found] ` <alpine.DEB.2.10.1307160134570.31834-6xBS8L8d439fDsnSvq7Uq4Se7xf15W0s1dQoKJhdanU@public.gmane.org>
@ 2013-07-16 8:21 ` Michael Kerrisk
0 siblings, 0 replies; 2+ messages in thread
From: Michael Kerrisk @ 2013-07-16 8:21 UTC (permalink / raw)
To: Vince Weaver; +Cc: Michael Kerrisk, linux-man-u79uwXL29TY76Z2rM5mHXA
On 07/16/13 07:36, Vince Weaver wrote:
>
> This improves the documentation of the various perf_event_open()
> related sysfs files.
Thanks, Vince. Applied.
Cheers,
Michael
> Signed-off-by: Vince Weaver <vincent.weaver-e7X0jjDqjFGHXe+LvDLADg@public.gmane.org>
>
> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
> index 504e801..e7ddcb2 100644
> --- a/man2/perf_event_open.2
> +++ b/man2/perf_event_open.2
> @@ -1926,6 +1926,7 @@ The default value is
>
> Maximum number of pages an unprivileged user can mlock (2) .
> The default is 516 (kB).
> +
> .RE
> Files in
> .I /sys/bus/event_source/devices/
> @@ -1936,30 +1937,59 @@ Information on how to program these PMUs can be found under
> .IR /sys/bus/event_source/devices/ .
> Each subdirectory corresponds to a different PMU.
> .TP
> -.I /sys/bus/event_source/devices/*/type
> +.IR /sys/bus/event_source/devices/*/type " (Since Linux 2.6.38)"
> This contains an integer that can be used in the
> .I type
> field of perf_event_attr to indicate you wish to use this PMU.
> .TP
> -.I /sys/bus/event_source/devices/*/rdpmc
> -[To be documented]
> +.IR /sys/bus/event_source/devices/*/rdpmc " (Since Linux 3.4)"
> +If this file is 1, then direct user-space access to the
> +performance counter registers is allowed via the rdpmc instruction.
> +This can be disabled by echoing 0 to the file.
> .TP
> -.I /sys/bus/event_source/devices/*/format/
> -This sub-directory contains information on what bits in the
> +.IR /sys/bus/event_source/devices/*/format/ " (Since Linux 3.4)"
> +This sub-directory contains information on the architecture-specific
> +sub-fields available for programming the various
> .I config
> -field of perf_event_attr correspond to.
> -.TP
> -.I /sys/bus/event_source/devices/*/events/
> +fields in the perf_event_attr struct.
> +
> +The content of each file is the name of the config field, followed
> +by a colon, followed by a series of integer bit ranges separated by
> +commas.
> +For example, the file
> +.I event
> +may contain the value
> +.I config1:1,6-10,44
> +which indicates that event is an attribute that occupies bits 1,6-10, and 44
> +of perf_event_attr::config1.
> +.TP
> +.IR /sys/bus/event_source/devices/*/events/ " (Since Linux 3.4)"
> This sub-directory contains files with pre-defined events.
> The contents are strings describing the event settings
> -expressed in terms of the fields found in the
> +expressed in terms of the fields found in the previously mentioned
> .I ./format/
> directory.
> These are not necessarily complete lists of all events supported by
> a PMU, but usually a subset of events deemed useful or interesting.
> +
> +The content of each file is a list of attribute names
> +separated by commas.
> +Each entry has an optional value (either hex or decimal).
> +If no value is specified than it is assumed to be a single-bit
> +field with a value of 1.
> +An example entry may look like this:
> +.I event=0x2,inv,ldlat=3
> .TP
> .I /sys/bus/event_source/devices/*/uevent
> -[To be documented]
> +This file is the standard kernel device interface
> +for injecting hotplug events.
> +.TP
> +.IR /sys/bus/event_source/devices/*/cpumask " (Since Linux 3.7)"
> +The cpumask file contains a comma-separated list of integers that
> +indicate a representative cpu number for each socket (package)
> +on the motherboard.
> +This is needed when setting up uncore or northbridge events, as
> +those PMUs present socket-wide events.
> .RE
> .SH RETURN VALUE
> .BR perf_event_open ()
>
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2013-07-16 5:36 perf_event_open() -- improve sysfs files documentation Vince Weaver
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2013-07-16 8:21 ` Michael Kerrisk
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