Add a manpage mostly taken from the source code comments and
the command help output.

Index: cpufrequtils/man/cpufreq-aperf.1
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ cpufrequtils/man/cpufreq-aperf.1	2012-05-06 13:29:37.943624564 +0900
@@ -0,0 +1,44 @@
+.TH "cpufreq-aperf" "1" "0.1" "Mattia Dongili" ""
+.SH "NAME"
+.LP
+cpufreq\-aperf \- Calculates the average frequency over a time period
+.SH "SYNTAX"
+.LP
+cpufreq\-aperf [\fIoptions\fP]
+.SH "DESCRIPTION"
+.LP
+On latest processors exist two MSR registers refered to as:
+  - MPERF increasing with maxium (P0) frequency in C0
+  - APERF increasing with current/actual frequency in C0
+
+From this information the average frequency over a time period can be
+calculated and this is what this tool does.
+
+A nice falloff feature beside the average frequency is the time
+a processor core remained in C0 (working state) or any CX (sleep state)
+processor sleep state during the measured time period. This information
+can be determined from the fact that MPERF only increases in C0 state.
+.SH "OPTIONS"
+.LP
+.TP
+\fB\-c\fR \fB\-\-cpu\fR <\fICPU\fP>
+ The <\fICPU\fP> core to measure - default all cores.
+.TP
+\fB\-i\fR \fB\-\-interval\fR <\fIseconds\fP>
+Refresh rate - default 1 second.
+.TP
+\fB\-o\fR \fB\-\-once\fR
+Exit after one interval.
+.TP
+\fB\-h\fR \fB\-\-help\fR
+Prints the available options.
+.SH "REMARKS"
+.LP
+The msr driver must be loaded for this command to work.
+.SH "AUTHORS"
+.nf
+Thomas Renninger <trenn@suse.de>
+.fi
+.SH "SEE ALSO"
+.LP
+cpufreq\-set(1), cpufreq\-info(1)
Index: cpufrequtils/man/cpufreq-info.1
===================================================================
--- cpufrequtils.orig/man/cpufreq-info.1	2012-05-06 11:56:21.215806103 +0900
+++ cpufrequtils/man/cpufreq-info.1	2012-05-06 13:29:37.943624564 +0900
@@ -73,4 +73,4 @@
 .fi
 .SH "SEE ALSO"
 .LP 
-cpufreq\-set(1)
+cpufreq\-set(1), cpufreq-aperf(1)
Index: cpufrequtils/man/cpufreq-set.1
===================================================================
--- cpufrequtils.orig/man/cpufreq-set.1	2012-05-06 11:56:21.215806103 +0900
+++ cpufrequtils/man/cpufreq-set.1	2012-05-06 13:29:37.943624564 +0900
@@ -53,4 +53,4 @@
 .fi
 .SH "SEE ALSO"
 .LP 
-cpufreq\-info(1)
+cpufreq\-info(1), cpufreq-aperf(1)
Index: cpufrequtils/Makefile
===================================================================
--- cpufrequtils.orig/Makefile	2012-05-06 11:56:21.215806103 +0900
+++ cpufrequtils/Makefile	2012-05-06 13:29:37.943624564 +0900
@@ -248,6 +248,7 @@
 install-man:
 	$(INSTALL_DATA) -D man/cpufreq-set.1 $(DESTDIR)${mandir}/man1/cpufreq-set.1
 	$(INSTALL_DATA) -D man/cpufreq-info.1 $(DESTDIR)${mandir}/man1/cpufreq-info.1
+	$(INSTALL_DATA) -D man/cpufreq-aperf.1 $(DESTDIR)${mandir}/man1/cpufreq-aperf.1
 
 install-gmo:
 	$(INSTALL) -d $(DESTDIR)${localedir}
@@ -270,6 +271,7 @@
 	- rm -f $(DESTDIR)${bindir}/cpufreq-aperf
 	- rm -f $(DESTDIR)${mandir}/man1/cpufreq-set.1
 	- rm -f $(DESTDIR)${mandir}/man1/cpufreq-info.1
+	- rm -f $(DESTDIR)${mandir}/man1/cpufreq-aperf.1
 	- for HLANG in $(LANGUAGES); do \
 		rm -f $(DESTDIR)${localedir}/$$HLANG/LC_MESSAGES/cpufrequtils.mo; \
 	  done;