rdtsc

问题 This question already has answers here : How to get the CPU cycle count in x86_64 from C++? (4 answers) Closed last year . With Visual Studio I can read the clock cycle count from the processor as shown below. How do I do the same thing with GCC? #ifdef _MSC_VER // Compiler: Microsoft Visual Studio #ifdef _M_IX86 // Processor: x86 inline uint64_t clockCycleCount() { uint64_t c; __asm { cpuid // serialize processor rdtsc // read time stamp counter mov dword ptr [c + 0], eax mov dword ptr [c +

问题 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 to ping). I am using rdtsc for getting high-resolution, low-overhead timing, which is needed by my implementation. All measurments looks reliable. Still, I am worried about rdtsc accuracy across cores, since I\'ve been reading some texts which implied that tsc is not synced between cores. I found the

问题 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 around the call to rdtscp. __asm__ __volatile__(\"rdtscp; \" // serializing read of tsc \"shl $32,%%rdx; \" // shift higher 32 bits stored in rdx up \"or %%rdx,%%rax\" // and or onto rax : \"=a\"(tsc) // output to tsc variable : : \"%rcx\", \"%rdx\"); // rcx and rdx are clobbered However, rdtscp is only

问题 On recent CPUs (at least the last decade or so) Intel has offered three fixed-function hardware performance counters, in addition to various configurable performance counters. The three fixed counters are: INST_RETIRED.ANY CPU_CLK_UNHALTED.THREAD CPU_CLK_UNHALTED.REF_TSC The first counts retired instructions, the second number of actual cycles, and the last is what interests us. The description for Volume 3 of the Intel Software Developers manual is: This event counts the number of reference

问题 I saw this post on SO which contains C code to get the latest CPU Cycle count: CPU Cycle count based profiling in C/C++ Linux x86_64 Is there a way I can use this code in C++ (windows and linux solutions welcome)? Although written in C (and C being a subset of C++) I am not too certain if this code would work in a C++ project and if not, how to translate it? I am using x86-64 EDIT2: Found this function but cannot get VS2010 to recognise the assembler. Do I need to include anything? (I believe