From mboxrd@z Thu Jan  1 00:00:00 1970
From: taeung <treeze.taeung@gmail.com>
Subject: What do zeroing of samples in 'perf top' mean ?
Date: Tue, 30 Sep 2014 12:19:41 +0900
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Cc: Namhyung Kim <namhyung@kernel.org>

Hi,

I have two questions about 'zeroing of samples' in 'perf top'.

I knew if I use 'perf top', I can see a performance counter profile in 
real time.
But I can't find a difference between 'perf top -a' and 'perf top --zero'.

After 'perf top' is run , I press key 'z' to toggle zeroing of samples.
But I don't know a difference between when I press key 'z' and before I 
did it.

1. What is 'Zero history' ?
(I saw it in Documentation/perf-top.txt that '--zero' option is 'Zero 
history across display updates.')

2. What do 'zeroing of samples' mean ?

Thanks,
Taeung