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

From: Peter Zijlstra
Date: Mon Jul 04 2011 - 07:08:56 EST


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)

AMD IBS also has load/store source information, from their data format a
single op can even be both a load and a store (atomic RMW ops might
qualify).

The problem with mapping this to IBS is that they don't have the L1/L2
split but simply say data-cache miss (but imply L3 is excluded from that
by having separate L3/DRAM bits).

Also, I really don't like the EXTRA name you gave it, if we're going to
do something like this it should really be about data source.


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