/* Measure time and sleep with IA-32 time-stamp counter. * * Author: Steffen Vogel * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University * SPDX-License-Identifier: Apache-2.0 */ #include #include using namespace villas; int tsc_init(struct Tsc *t) { #if defined(__x86_64__) || defined(__i386__) uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0; // Check if TSC is supported __get_cpuid(0x1, &eax, &ebx, &ecx, &edx); if (!(edx & bit_TSC)) return -2; // Check if RDTSCP instruction is supported __get_cpuid(0x80000001, &eax, &ebx, &ecx, &edx); t->rdtscp_supported = edx & bit_RDTSCP; // Check if TSC is invariant __get_cpuid(0x80000007, &eax, &ebx, &ecx, &edx); t->is_invariant = edx & bit_TSC_INVARIANT; // Intel SDM Vol 3, Section 18.7.3: // Nominal TSC frequency = CPUID.15H.ECX[31:0] * CPUID.15H.EBX[31:0] ) รท CPUID.15H.EAX[31:0] __get_cpuid(0x15, &eax, &ebx, &ecx, &edx); if (ecx != 0) t->frequency = ecx * ebx / eax; else { #ifdef __linux__ int ret = kernel::get_cpu_frequency(&t->frequency); if (ret) return ret; #endif } #else #ifdef __linux__ int ret = kernel::get_cpu_frequency(&t->frequency); if (ret) return ret; #endif #endif if (t->frequency) return 0; // Frequency determined with success else return -1; } uint64_t tsc_rate_to_cycles(struct Tsc *t, double rate) { return t->frequency / rate; }