unsigned int lo = 0; unsigned int hi = 0; __asm__ __volatile__ ( "mfence;rdtsc" : "=a"(lo), "=d"(hi) : : "memory" ); mfence in the above code, is it necessary? Based on my test, cpu reorder is ...

I want to get the CPU cycles at a specific point. I use this function at that point: static __inline__ unsigned long long rdtsc(void) { unsigned long long int x; __asm__ volatile (".byte 0x0f, 0...

I'm looking into measuring benchmark performance using the time-stamp register (TSR) found in x86 CPUs. It's a useful register, since it measures in a monotonic unit of time which is immune to the ...

I'm stuck in the problem as the title says.I want to do this in VMM by adding the CPU_BASED_RDTSC_EXITING flag in vmx.c(arch/x86/kvm) in setup_vmcs_config function,and then handle the vm_exit by...

I have a piece of code running on MSVC 2012: #include <windows.h> #include <intrin.h> UINT64 gettime() { try { unsigned int ui; return __rdtscp(&ui); } catch (...) { return...

I am trying to use RDTSC but it seems like my approach may be wrong to get the core speed: #include "stdafx.h" #include <windows.h> #include <process.h> #include <iostream> usin...

I am sending network packets from one thread and receiving replies on a 2nd thread that runs on a different CPU core. My process measures the time between send & receive of each packet (similar...

I know that rdtsc loads the current value of the processor's time-stamp counter into the two registers: EDX and EAX. In order to get it on x86 I need to do it like that (assuming using Linux): un...

Assume we're trying to use the tsc for performance monitoring and we we want to prevent instruction reordering. These are our options: 1: rdtscp is a serializing call. It prevents reordering aro...

It seems most newer CPUs from both AMD and Intel implement rdtsc as a constant rate counter, avoiding the issues caused by frequency changing as a result of things like TurboBoost or power saving s...

#include <stdio.h> static inline unsigned long long tick() { unsigned long long d; __asm__ __volatile__ ("rdtsc" : "=A" (d) ); return d; } int main() { long long res; res=tick(); res...

I'm constructing a micro-benchmark to measure performance changes as I experiment with the use of SIMD instruction intrinsics in some primitive image processing operations. However, writing useful ...

I am studying RDTSC and learning about how it is virtualized for the purposes of virtual machines like VirtualBox and VMWare. Why did Intel/AMD go to all the trouble of virtualizing this instructio...