On 12/24/2013 10:27 PM, Andi Kleen wrote:
I checked what can be measured with the offcore facility. I can ask
to count remote memory accesses, but now I am not sure PEBS is
enable for these events. If the answer is no, I can't accurately
identify remote memory accesses with offcore events ? As a
consequence I am wondering if there is a way to do such thing ?
The OFFCORE events are not PEBS enabled.
Ok, you confirm what I read in the Intel SDM.
However the memory PEBS
events report the same information (with some limitations) in
the PEBS record (and perf reports this information)
By memory PEBS events, do you mean the following events ?
MEM_LOAD_RETIRED.L1D_MISS
MEM_LOAD_RETIRED.L1D_LINE_MISS
MEM_LOAD_RETIRED.L2_MISS
MEM_LOAD_RETIRED.L2_LINE_MISS
MEM_LOAD_RETIRED.DTLB_MISS
I can't profile memory accesses with these events, isn't it ? What do
you mean by perf reports this infomation, which perf tool ?
In general you cannot accurately profile all memory accesses.
Does it means that the perf mem record tool is reporting wrong values
concerning the source of the event ? (I checked that this tool use the
load latency event with PEBS and you said that the IP reported by this
uncore event is not always the correct one ?)
Thanks,
----
Manu
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