Most Intel microprocessors support “HyperThreading” (Intel’s trademark for their implementation of “simultaneous multithreading”) — which allows the hardware to support (typically) two “Logical Processors” for each physical core. Processes running on the two Logical Processors share most of the processor resources (particularly caches and execution units). Some workloads (particularly heterogeneous… read more
Performance
Why I hate MPI (from a performance analysis perspective)
According to Dr. Bandwidth, performance analysis has two recurring themes: How fast should this code (or “simple” variations on this code) run on this hardware? If I am analyzing (apparent) performance shortfalls, how can I distinguish between cause and effect? For very simple codes, it may be possible to do… read more
Comments on timing short code sections on Intel processors
(From a recent post of mine on the Intel software developer forums — some potentially useful words to go along with my new low-overhead-timers project…) Updates on 2019-01-23 in blue. There are lots of topics that you need to be aware of when attempting fine-grain timing. A few of the… read more