Take a look at cat /proc/stat grep ‘cpu ‘ /proc/stat | awk ‘{usage=($2+$4)*100/($2+$4+$5)} END {print usage “%”}’ EDIT please read comments before copy-paste this or using this for any serious work. This was not tested nor used, it’s an idea for people who do not want to install a utility or for something that works … Read more
Along the lines of what I mentioned in this post. I recommend you use the SIGAR API. I use the SIGAR API in one of my own applications and it is great. You’ll find it is stable, well supported, and full of useful examples. It is open-source with a GPL 2 Apache 2.0 license. Check … Read more
If your threads don’t do I/O, synchronization, etc., and there’s nothing else running, 1 thread per core will get you the best performance. However that very likely not the case. Adding more threads usually helps, but after some point, they cause some performance degradation. Not long ago, I was doing performance testing on a 2 … Read more
What is this warning about? Modern CPUs provide a lot of low-level instructions, besides the usual arithmetic and logic, known as extensions, e.g. SSE2, SSE4, AVX, etc. From the Wikipedia: Advanced Vector Extensions (AVX) are extensions to the x86 instruction set architecture for microprocessors from Intel and AMD proposed by Intel in March 2008 and … Read more
The cardinal rules of speculative out-of-order (OoO) execution are: Preserve the illusion of instructions running sequentially, in program order Make sure speculation is contained to things that can be rolled back if mis-speculation is detected, and that can’t be observed by other cores to be holding a wrong value. Physical registers, the back-end itself that … Read more
The psutil library gives you information about CPU, RAM, etc., on a variety of platforms: psutil is a module providing an interface for retrieving information on running processes and system utilization (CPU, memory) in a portable way by using Python, implementing many functionalities offered by tools like ps, top and Windows task manager. It currently … Read more
Windows Some of the above values are easily available from the appropriate Win32 API, I just list them here for completeness. Others, however, need to be obtained from the Performance Data Helper library (PDH), which is a bit “unintuitive” and takes a lot of painful trial and error to get to work. (At least it … Read more