cpu

I would like to measure CPU time of some function. I know how to use GetProcessTimes , but I have a problem implementing it with some kind of 'restarting': Normally, I would do it like this: #include "stdafx.h" #include <math.h> #include <windows.h> double cputimer() { FILETIME createTime; FILETIME exitTime; FILETIME kernelTime; FILETIME userTime; if ( GetProcessTimes( GetCurrentProcess( ), &createTime, &exitTime, &kernelTime, &userTime ) != -1 ) { SYSTEMTIME userSystemTime; if ( FileTimeToSystemTime( &userTime, &userSystemTime ) != -1 ) return (double)userSystemTime.wHour * 3600.0 + (double

To simulate 100% CPU usage, I placed an infinite while loop in my code ( while (true) { } ) . This seemed to spike the CPU usage up to 30% (ordinarily it is 2% for the same program that I run without the while loop). Why does it not go above 30%? This is a dual core Intel i7 processor. The app is a simple console app running c# code on .net 4.0 private static void SimulateCPUSpike() { while(true) { } } CPU usage is a percentage of all CPU cores. If your code is only running a single thread, it cannot occupy more than one core. You need to make a separate thread for each core. ( Environment

Are Intel x86_64 processors not only pipelined architecture, but also superscalar? Pipelining - these two sequences execute in parallel (different stages of the same pipeline-unit in the same clock, for example ADD with 4 stages): stage1 -> stage2 -> stage3 -> stage4 -> nothing nothing -> stage1 -> stage2 -> stage3 -> stage4 Superscalar - these two sequences execute in parallel (two instructions can be launched to different pipeline-units in the same clock, for example ADD and MUL): ADD(stage1) -> ADD(stage2) -> ADD(stage3) MUL(stage1) -> MUL(stage2) -> MUL(stage3) Yes, contemporary Intel

When we have a CPU that supports some form of multithreading, each logical CPU has it's own set of registers (as a minimum), including a CR3 register. Since we are working on the vitual address space of the same process when executing different threads and a context switch never happens (neither the TLB cache gets invalidated when switching threads of the same process), why do we need a CR3 register to point to the page table and page directory in the logical CPU? Isn't the value always the same as the value in the CR3 of the physcial CPU? Since we are working on the vitual address space of

At 29min mark of http://channel9.msdn.com/Events/GoingNative/2013/Writing-Quick-Code-in-Cpp-Quickly Andrei Alexandrescu says when using constants to prefer 0 and mentions hardware knows how to handle it. I did some assembly and I know what he is talking about and about the zero flag on CPUs Then he says prefer the constant 1 rather then -1. -1 IIRC is not actually special but because it is negative the sign flag on CPUs would be set. 1 from my current understanding is simply a positive number there is no bit on the processor flag for it and no way to distinguish from 0 or other positive