topic CACHESIZE for i7-4770 in Intel® Fortran Compiler

CACHESIZE for i7-4770

Don_Ritchie — Tue, 20 Aug 2013 18:31:18 GMT

I'm running Visual Fortran Composer XE 2011 Update 11 under Windows 7 64-bit on a new machine with the Intel Core i7-4770 which has caches L1=256 kB, L2=1024 kB, L3=8192 kB. The CACHESIZE(n) generic Intrinsic Function, however, returns CACHESIZE(1)->32, CACHESIZE(2)->256, CACHESIZE(3)->8192.

This is not a critical problem for me at this time, but everyone might like to be aware of it.

You may also be interested in knowing about my 7/24/13 post: "crashes of gemm on new Windows machine" in the mkl forum.

Interesting - would you

Steven_L_Intel1 — Tue, 20 Aug 2013 18:47:39 GMT

Interesting - would you please download, install and run the Intel Processor Identification Utility, Click File > Save, save a report and attach it to a reply here? I'd like to see what that utility reports on your system.

Steve:

Don_Ritchie — Tue, 20 Aug 2013 19:31:00 GMT

Steve:

Attached is the output file from the Processor ID Utility.

Apparently the size reported by CACHESIZE(n) for n=1 or 2 is size per core. So the problem is/was my misunderstanding of the specs for the i7-4770 which give 'total' L1 and L2 caches.

Thanks for clearing that up.

Yes, that seems to be correct

Steven_L_Intel1 — Tue, 20 Aug 2013 19:37:29 GMT

Yes, that seems to be correct. Glad that we got that cleared up. The motivation for the function was to help with algorithms that dynamically adjust the way they traverse arrays based on cache size. It would make sense for this to be per-core. The L3 cache is shared by all cores.