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Interpreting percentage of clockticks in vtune

Anoop11
Beginner
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Anoop11_0-1738361351385.png

 

In the above screenshot, is the 56.2% of clockticks for DRAM Bound 56.2% of all clockticks that occurred during the collection?

 

If that is the case, the 84.2% of clockticks for Local Memory can't be the percentage of all clockticks, right, because that couldn't be larger than 56.2. So is the 84.2% number the percentage of the 56.2% of DRAM clockticks?

 

Finally, is the percentage of total clockticks proportional to the percentage of elapsed time? For example, if I understand correctly that we have 54.3% of all clockticks spent reading DRAM, and since the elapsed time is 49.914 seconds, is the amount of time spent accessing DRAM 0.543*49.914 = 27.103302 seconds?

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yuzhang3_intel
Moderator
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The uarch-exploration is based on TMA, all the CPU metrics are defined in the file below, you can refer:

https://github.com/intel/perfmon/blob/main/TMA_Metrics-full.xlsx

 

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Anoop11
Beginner
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The MEM_Bandwidth row has no entries except for SNB (Sandy Bridge if I understand correctly). My machine is Skylake. Should I assume the metric is calculated the same way as for SNB?

 

Also, do you think you could answer this question directly: is the percentage of total clockticks proportional to the percentage of elapsed time?

 

If you could answer my first two questions directly as well, that would also be helpful.

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yuzhang3_intel
Moderator
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Yes, the SKL uses the same formula as SNB.

 

From the formula, the percentage of total clockticks should be proportional to the percentage of elapsed time.

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