topic Identifying false sharing on Xeon 5600 series in Intel® Moderncode for Parallel Architectures

Identifying false sharing on Xeon 5600 series

zoolii — Tue, 31 Aug 2010 14:57:33 GMT

Hi All,

Any idea about how to identify false sharing on xeon 5600 series. I found an article http://software.intel.com/en-us/articles/avoiding-and-identifying-false-sharing-among-threads/which describes same for core 2 duo and core i7 . Or whatever applicable to core i7 will also be applicable to Xeon also ?. But PTU does not give options to add MEM_UNCORE_RETIRED.OTHER_CORE_L2_HITM (as describedin the article) on Xeon E5640.

Thank you,
Zooli

Identifying false sharing on Xeon 5600 series

TimP — Wed, 01 Sep 2010 01:24:17 GMT

PTU core I7 options apply equally to Xeon 5600. False sharing will be more severe on account of the unshared caches.

Identifying false sharing on Xeon 5600 series

Roman_D_Intel — Wed, 01 Sep 2010 08:29:06 GMT

Hi Zooli,

do you see any of MEM_UNCORE_RETIRED.* events in PTU on your CPU?

I can also recommend to try the most recent update of VTune Performance Analyzer (there was one of maybe two updates published this summer) instead of PTU. I remember it should have support of Xeon 5600 series.

Roman

Identifying false sharing on Xeon 5600 series

zoolii — Thu, 02 Sep 2010 04:57:06 GMT

Hi Roman,

I was using VMWare and VTunewill not run on VMWare. I will try VTune on a real machine.

Thank you,
Zooli

Identifying false sharing on Xeon 5600 series

Roman_D_Intel — Mon, 06 Sep 2010 14:19:20 GMT

Hi Zooli,

as far as I know CPU event sampling (both in PTU and in VTune) is not supposed to work in a virtual machine.

Roman