Software Tuning, Performance Optimization & Platform Monitoring
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Monitoring DTLB events?

Adrian_C_1
Beginner
138 Views

Hi!

How much detail can I drill into with the TLB performance counters? In particular, I'd like to see how effective the 2mb/1gb TLB entries are. Are there any counters that let me see hits/misses for the TLB based on the page table entry size?

Thanks!

-adrian

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5 Replies
Bernard
Black Belt
138 Views

Did try to consult E3 or E5 processor datasheets?

Patrick_F_Intel1
Employee
138 Views

We do need to know which chip you are using.

Bernard
Black Belt
138 Views

I need to look through SDM.

Adrian_C_1
Beginner
138 Views

Hi!

It's more a general question than a chipset specific question, as I'm interested on a variety of platforms - anything Nehalem and later.

But my immediate need is for Sandy Bridge Xeon (E5-2650). I'm also interested for Ivy Bridge and the server version of Ivy Bridge that I hear is coming out soon.

I did read the SDM chapter on performance counting. DTLB_LOAD_MISSES.* is kind of there. It does have 4k and 2M/4M page walks but not 1G page walks. It also only has the page size specifics in table 19-2 (Non-arch perf events, 4th generation intel core processors) and nothing in the SB or SB Xeon tables about this. It also has DTLB_LOAD_MISSES.WALK_DURATION which is the cycles busy doing a walk; I want to be able to filter _that_ by the page size if possible.

In any case, being able to count the 1G page walks would be really, really helpful.

Thanks!

-a

Bernard
Black Belt
138 Views

Why do you need 1gb page walks cycles latency?Do you have a large amount of physical ram or does your application needs so much memory to utilize large pages? 

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