RDTSC — Read Time-Stamp Counter - felixcloutier.com
WEBRDTSC — Read Time-Stamp Counter. Instruction Operand Encoding ¶. Description ¶. Reads the current value of the processor’s time-stamp counter (a 64-bit MSR) into the EDX:EAX registers. The EDX register is loaded with the high-order 32 bits of the MSR and the EAX register is loaded with the low-order 32 bits.
Introduction to RDTSC - Computer, Enhance!
WEBJun 14, 2023 · Introduction to RDTSC. Originally a measurement of actual core cycles elapsed, RDTSC is now more like a wall clock timer than an instruction cycle timer. Share. This is the fourth video in Part 2 of the Performance-Aware Programming series. Please see the Table of Contents to quickly navigate through the rest of the course as it is updated …
linux - Getting cpu cycles using RDTSC - Stack Overflow
WEBOct 21, 2016 · 20. 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, 0x31" : "=A" (x)); // broken for 64-bit builds; don't copy this code. return x; } (editor's note: "=A" is wrong for x86-64; it picks either RDX or RAX.
__rdtsc | Microsoft Learn
WEBAug 2, 2021 · Requirements. Remarks. Show 2 more. Microsoft Specific. Generates the rdtsc instruction, which returns the processor time stamp. The processor time stamp records the number of clock cycles since the last reset. Syntax. Copy. unsigned __int64 __rdtsc(); Return value. A 64-bit unsigned integer representing a tick count. …
c - Best practice of using __rdtsc - Stack Overflow
WEBApr 20, 2023 · The normal state of affairs is the many instructions are in flight in the CPU's out-of-order execution machinery. Often what matters is the throughput cost of your code, not the end-to-end latency of a small snippet that the CPU can overlap with surrounding code. So anything like rdtscp(&dummy) or _mm_lfence(); __rdtsc() to wait for all earlier ...
GitHub - xuwd1/rdtsc-notes: notes and example codes on using rdtsc…
WEBStackoverflow thread. Intel's guide on benchmarking code with rdtsc (p) rdtscp reference. rdtsc reference. First glance. For measuring the execution time of work, the ideal case would be like the following: leading_code () startcycle = rdtsc () measured_code () endcycle = rdtsc () following_code () However things just won't work out this easy.
Why is RDTSC a virtualized instruction on modern processors?
WEBOct 12, 2011 · 124k 13 143 231. Okay, I get why you would need virtualization for very fine-grained timing of a short sequence of instructions. However, the only reason I can think of for doing this is research purposes, or side-channel attacks. Are there any legitimate reasons? It almost feels like virtualization of rdtsc is evil. – Robert Martin.
Difference between rdtscp, rdtsc : memory and cpuid / rdtsc?
WEBSep 28, 2012 · 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. : …
RDTSCP — Read Time-Stamp Counter and Processor ID
WEBRDTSCP — Read Time-Stamp Counter and Processor ID. Instruction Operand Encoding ¶. Description ¶. Reads the current value of the processor’s time-stamp counter (a 64-bit MSR) into the EDX:EAX registers and also reads the value of the IA32_TSC_AUX MSR (address C0000103H) into the ECX register.
RDTSC—Read Time-Stamp Counter - GitHub Pages
WEBRDTSC—Read Time-Stamp Counter. Instruction Operand Encoding. Description. Reads the current value of the processor’s time-stamp counter (a 64-bit MSR) into the EDX:EAX registers. The EDX register is loaded with the high-order 32 bits of the MSR and the EAX register is loaded with the low-order 32 bits.
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