From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chulmin Kim <cmkim@core.kaist.ac.kr>
Subject: Question about LLC-load-misses event
Date: Mon, 15 Oct 2012 22:07:43 +0900
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Hi, all.

I'm currently evaluating memory performance of my own machine (intel
x5650 cpu).
My machine can have NUMA configuration, but it is under control. (only
local mem access allowed)

As i run STREAM benchmark, i monitor LLC cache misses using "perf"
simultaneously.
(perf command : perf stat -a -A -e LLC-loads -e LLC-load-misses -e
instructions sleep 3)

The problem is,, the bandwidth from STREAM benchmark does not match with
the monitored value.

e.g.
I got 9395MB/s from Stream.

"perf" shows 134,642,063 LLC-load-misses for 3 seconds.
-> BW = ((# of events)/(3 seconds)) * 64 bytes / (1024*1024) = 2739MB/s
In this equation, the term (64bytes) is for cache line size, and the
term(1024*1024) is for (MB/s).

Why does this mismatch occur?