Messages in this thread | | | Date | Fri, 30 Jun 2017 15:03:13 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] selftests: ftrace: Use md5sum to take less time of checking logs |
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On Fri, 30 Jun 2017 20:50:45 +0200 Denys Vlasenko <vda.linux@googlemail.com> wrote:
> On Tue, Jun 27, 2017 at 12:28 PM, Masami Hiramatsu <mhiramat@kernel.org> wrote: > > Use md5sum so that it takes less time of checking > > trace logs update. Since busybox tail/cat takes too > > long time to read the trace log, this uses md5sum > > to check whether trace log is updated or not. > > > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > > --- > > .../test.d/ftrace/func_traceonoff_triggers.tc | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc > > index 9cf3852..7a9ab4f 100644 > > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc > > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc > > @@ -103,11 +103,11 @@ if [ $on != "0" ]; then > > fail "Tracing is not off" > > fi > > > > -line1=`cat trace | tail -1` > > +csum1=`md5sum trace` > > sleep $SLEEP_TIME > > -line2=`cat trace | tail -1` > > +csum2=`md5sum trace` > > If you replace that with "tail -1 <trace", this code > in busybox will be used: > > off_t current = lseek(fd, 0, SEEK_END);
The trace file is a kernel pseudo file that prevents lseek. Now what you could do is:
cat trace > tempfile csum1=`tail -1 <tempfile`
But then we need to make sure to clean up the files.
-- Steve
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