Re: [PATCH 1/4] perf: Add memory load/store events generic code

From: Peter Zijlstra
Date: Tue Jul 05 2011 - 08:04:06 EST


On Mon, 2011-07-04 at 10:44 +0200, Peter Zijlstra wrote:
> On Mon, 2011-07-04 at 10:33 +0200, Peter Zijlstra wrote:
> > On Mon, 2011-07-04 at 08:02 +0000, Lin Ming wrote:
> > > +/*
> > > + * Memory load operation info encoding
> > > + */
> > > +
> > > +/* Bits(0-1) {L1, L2, L3, RAM} or {unknown, IO, uncached, reserved}
> > > */
> > > +#define MEM_LOAD_L1 0x00
> > > +#define MEM_LOAD_L2 0x01
> > > +#define MEM_LOAD_L3 0x02
> > > +#define MEM_LOAD_RAM 0x03
> > > +#define MEM_LOAD_UNKNOWN 0x00
> > > +#define MEM_LOAD_IO 0x01
> > > +#define MEM_LOAD_UNCACHED 0x02
> > > +#define MEM_LOAD_RESERVED 0x03
> > > +
> > > +/* Bits(2-3) {toggle, snoop, local, remote} */
> > > +#define MEM_LOAD_TOGGLE (0x00 << 2)
> > > +#define MEM_LOAD_SNOOP (0x01 << 2)
> > > +#define MEM_LOAD_LOCAL (0x02 << 2)
> > > +#define MEM_LOAD_REMOTE (0x03 << 2)
> > > +
> > > +/* Bits(4-5) {modified, exclusive, shared, invalid} */
> > > +#define MEM_LOAD_MODIFIED (0x00 << 4)
> > > +#define MEM_LOAD_EXCLUSIVE (0x01 << 4)
> > > +#define MEM_LOAD_SHARED (0x02 << 4)
> > > +#define MEM_LOAD_INVALID (0x03 << 4)
> >
> > Did anybody check with the other PMUs that have similar features like
> > PowerPC and possibly IA64?
> >
> > I keep mentioning this, nobody seems interested.
>
> Anton, Paulus, IIRC PowerPC had some sort of Data-Source indication,
> would you have some docs available on the PowerPC PMU?

Going through
http://www.power.org/resources/downloads/PowerISA_V2.06B_V2_PUBLIC.pdf

Book III-S, Appendix B

I can only find the SDAR thing (which I assume is what PERF_SAMPLE_DATA
uses) but no mention of extra bits describing where the data was sourced
from. For some reason I had the impression PPC64 had the capability to
tell if a load/store was from/to L1/2/3/DRAM etc.

Now since the above document is in fact not an exhaustive spec of a
particular chip but more an outline of what a regular ppc64 chip should
have, with lots of room for implementation specific extensions it
doesn't say much at all.

So do you know of such a feature for PPC64 and if so, where's the
docs? :-)
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