trace-cmd/split: Force percpu when parsing by pages is set

When parsing by pages is set, we automatically set the percpu parsing.
This is because non percpu does not make sense. The CPU data is stored
per page and two or more CPU data is not shared on a single CPU data page.

This patch forces the -c option (percpu) when the -p option is set.
Previously the -p option without the -c option gave some strange results.
Usually just one or two events per page.

Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/trace-cmd-split.1.txt b/Documentation/trace-cmd-split.1.txt
index d061f39..1c16805 100644
--- a/Documentation/trace-cmd-split.1.txt
+++ b/Documentation/trace-cmd-split.1.txt
@@ -60,6 +60,8 @@ OPTIONS
 
    Note: only one of *-p*, *-e*, *-u*, *-m*, *-s* may be specified at a time.
 
+   If *-p* is specified, then *-c* is automatically set.
+
 *-r*::
     This option causes the break up to repeat until end-time is reached (or
     end of the input if end-time is not specified).
diff --git a/trace-split.c b/trace-split.c
index 9e74554..a75554e 100644
--- a/trace-split.c
+++ b/trace-split.c
@@ -441,6 +441,10 @@ void trace_split (int argc, char **argv)
                         if (count <= 0)
                                 die("Units must be greater than 0");
                         split_type = type;
+
+                        /* Spliting by pages only makes sense per cpu */
+                        if (type == SPLIT_PAGES)
+                                percpu = 1;
                         break;
                 case 'r':
                         repeat = 1;