Messages in this thread |  | | Date | Wed, 18 Feb 2015 05:58:05 +0100 | From | Andi Kleen <> | Subject | Re: [PATCH 1/3] perf, x86: Add new cache events table for Haswell |
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On Thu, Feb 12, 2015 at 10:28:06PM +0100, Peter Zijlstra wrote: > 1) SDM (2014-09) says in 18.9.5 (snb offcore): > > "software must set at least one request type bit and a valid response > type pattern" > > and > > "A valid response type must be a non-zero value of the following > expression: > > ANY | [('OR' of Supplier Info Bits) & ('OR' of Snoop Info Bits)]" > > Is this still valid for the HSW part?
Yes.
However they need to be set on Sandy Bridge to work around an issue. On HSW they don't hurt at least.
> #define HSW_LLC_ACCESS (HSW_ANY_RESPONSE) > #define HSW_LLC_MISS (HSW_L3_MISS|HSW_ANY_SNOOP) > > Would be the suitable helpers to use here. No need to set Supplier and > Snoop bits for ANY_RESPONSE.
Ok.
> 2) I know I included it on SNB, but would SNOOP_HITM really be a miss? > From what I can tell it could be a local MtoS w/ WB or so. Do we count > it as a miss because the WB part goes to DRAM so we still get to wait > for it (just in the 'wrong' direction)?
SNOOP_HITM is a miss because M is only present in one cache. So it's a miss for the requester.
> > 3) While we're there, will we get SNOOP_FWD only for Clean forwards or > also for the HITM forwards; the SDM is vague -- it would be nice if > SNOOP_FWD was a selector for all remote socket snoops.
It's only for clean forwards.
> > > + [ C(NODE) ] = { > > + [ C(OP_READ) ] = { > > + [ C(RESULT_ACCESS) ] = HSW_DEMAND_READ| > > + HSW_L3_MISS_LOCAL_DRAM|HSW_SUPPLIER_NONE| > > + HSW_ANY_SNOOP, > > 4) SUPPLIER_NONE; I'll interpret it as specific event that lacks other > supplier info (as opposed to _any_ supplier). What kind of events would > this be?
Your interpretation is right. Ok, we can drop it. It should rarely happen.
> > I didn't include SUPPLIER_NONE in any events on SNB, its implied by > L3_ACCESS due to ANY, but other than that I'm not sure what to do with > it. It seems out of place for DRAM_ANY. > > 5) NODE-ACCESS is _any_ DRAM; > NODE-MISS is remote DRAM. > > for SNB I didn't include NON_DRAM in ANY_SNOOP for this reason. > > #define HSW_DRAM_ANY (HSW_LLC_MISS & ~HSW_SNOOP_NON_DRAM) > #define HSW_DRAM_REMOTE (HSW_MISS_LOCAL_DRAM|HSW_ANY_SNOOP & ~HSW_SNOOP_NON_DRAM)
This should be more like HSW_L3_MISS_REMOTE_HOP0|HSW_L3_MISS_REMOTE_HOP1|HSW_L3_MISS_REMOTE_HOP2P|HSW_ANY_SNOOP & ~HSW_SNOOP_NON_DRAM)
> > 6) Should we maybe use > > (SNOOP_ANY & ~(SNOOP_HIT_NO_FWD|NON_DRAM)) > > instead for DRAM_REMOTE? SNOOP_HIT_NO_FWD seem as inappropriate as > NON_DRAM for REMOTE.
SNOOP_HIT_NO_FWD indicates DRAM.
-Andi
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