popcnt latency/throughput in 64bits

[matthieu_darbois]

Hi,

I could find these values for 32bits operations in the last Optimization Reference Manual but the counter part for 64bits operations is not there.

Does anyone know where I can find this ?

Reagrds,

Matthieu

[Aubrey_W_]

Hi Mattheiu,

POPCNT is an SSE4 instruction. You might try looking in the Intel SSE4 Programming Reference here:
http://software.intel.com/en-us/articles/45nm-next-generation-intel-coret-2-processor-family-penryn-and-intel-streaming-simd-extensions-4-intel-sse4/

AVX reference can be found at http://software.intel.com/en-us/avx/

I hope that helps.

==
Aubrey W.
Intel Software Network Support

[matthieu_darbois]

Hi,

This was not the kind of information I was looking for. I've used this instruction for a while now and thus, I know that it is SSE4.2 or SSE4a on AMD. In fact, just have to look for the POPCNT flag in CPUID...

What I am looking for is the performance of this instruction. As I said in the first post, the "Intel 64 and IA-32ArchitecturesOptimization Reference Manual" (Order Number: 248966-020) lists in Appendix C almost all throughput and latency values for SIMD extensions.

However, I can't find these values for POPCNT in 64 bits flavour.

Regards,

Matthieu

[Max_L · Accepted solution]

Hello Matthieu - POPCNT has the same 3-cycle latency / 1-cycle throughputfor both 32-bit and 64-bit forms.

Regards,
-Max

[matthieu_darbois]

Hi Max,

Thanks for this answer.

Is there anyway to post comments/ request additional information like this to be put in the reference manual ?

Regards,

Matthieu