bug#31226: [PATCH] gnu: Add libpfm4.

[Ludovic Courtès]

Rouby Pierre-Antoine <address@hidden> skribis:

> * gnu/packageslinux.scm (libpfm4): New variable.

Applied with the following changes based on their README.

Thank you!

Ludo’.

diff --git a/gnu/packages/linux.scm b/gnu/packages/linux.scm
index b6d00c853..4d2446317 100644
--- a/gnu/packages/linux.scm
+++ b/gnu/packages/linux.scm
@@ -4712,12 +4712,18 @@ high-speed networking devices.")
                                 (string-append "PREFIX=" out)
                                 "install")
                         #t))))))
-    (synopsis "Performance events monitoring library for Linux perf_events")
+    (synopsis "Performance event monitoring library")
     (description
-     "This package is a user library called libpfm4 to help setup performance
-events for use with the perf_events Linux kernel interface.
+     "This package provides a library called libpfm4, which is used to develop
+monitoring tools exploiting the performance monitoring events such as those
+provided by the Performance Monitoring Unit (PMU) of modern processors.
 
-This is a complete rewrite of libpfm3 and it is NOT backward compatible
-with it.")
+Libpfm4 helps convert from an event name, expressed as a string, to the event
+encoding that is either the raw event as documented by the hardware vendor or
+the OS-specific encoding.  In the latter case, the library is able to prepare
+the OS-specific data structures needed by the kernel to setup the event.
+
+libpfm4 provides support for the @code{perf_events} interface, which was
+introduced in Linux 2.6.31.")
     (home-page "http://perfmon2.sourceforge.net/";)
     (license license:expat)))