Hi Fabian, let us meet tomorrow at 10 am and try to understand the output. Vitali On 09/07/2016 05:22 PM, Delalondre Fabien Jonathan wrote:

Hi All,

I am trying to benchmark and understand performance using Vtune memory bandwidth analysis when allocating memory in DRAM and MCRAM explicitly using both memkind and hbwmalloc interface (on a toy example).

The KNL config I used is FLAT/Quadrant. I am just using a single core with 4 omp threads and I am not sure to understand the results I am getting from vtune.

Who would feel kind enough and comfortable enough with Vtune to spend 15-20min with me maybe tomorrow ?

Few questions:

1) Even though I allocate memory first in DRAM, then in MCDRAM (adding a barrier between the two), Vtune seems to indicate DRAM/MCDRAM memory bandwidth utilisation is overlapping as if it would read data from both MCDRAM/DRAM at the same time.

Note that I make sure to explicitly initialise memory to force the allocation.

2) What's the difference between package and channel memory in this context. I would expect the channel to be the memory channel monitored. But then... if I am using a single core, why is the DRAM package memory bandwidth different from the channel one...

Thanks for your help.

Fabien

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