Re: [perfmon] Re: [perfmon2] perfmon2 merge news

[dean gaudet <dean@arctic.org>]

On Wed, 14 Nov 2007, Andi Kleen wrote:

> Later a syscall might be needed with event multiplexing, but that seems
> more like a far away non essential feature.

actually multiplexing is the main feature i am in need of. there are an 
insufficient number of counters (even on k8 with 4 counters) to do 
complete stall accounting or to get a general overview of L1d/L1i/L2 cache 
hit rates, average miss latency, time spent in various stalls, and the 
memory system utilization (or HT bus utilization).  this runs out to 
something like 30 events which are interesting... and re-running a 
benchmark over and over just to get around the lack of multiplexing is a 
royal pain in the ass.

it's not a "far away non-essential feature" to me.  it's something i would 
use daily if i had all the pieces together now (and i'm constrained 
because i cannot add an out-of-tree patch which adds unofficial syscalls 
to the kernel i use).

-dean
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