Gabriele Fatigati, le Thu 04 Aug 2011 16:35:36 +0200, a écrit : > so physical OS index 0 and 1 are not true are physically near on the die.
They quite often aren't. See the updated glossary of the documentation: "The index that the operating system (OS) uses to identify the object. This may be completely arbitrary, non-unique, non-contiguous, not representative of proximity, and may depend on the BIOS configuration." > Considering that, how I can use cache locality and cache sharing by cores if I > don't know where my threads will physically bound? By using logical indexes, not physical indexes. And almost all hwloc functions use logical indexes, not physical indexes. > If L#0 and L#1 where I bind my threads are physically far, may give me bad > performance. L#0 and L#1 are physically near, that's precisely the whole point of hwloc: it provides you with *logical* indexes which express proximity, instead of the P#0 and P#1 physical/OS indexes, which are quite often simply arbitrary. Samuel
