1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "util.h" 18 19 #include <err.h> 20 #include <math.h> 21 #include <sched.h> 22 #include <stdio.h> 23 #include <string.h> 24 #include <wchar.h> 25 26 #include <cstdlib> 27 28 // This function returns a pointer less than 2 * alignment + or_mask bytes into the array. 29 char* GetAlignedMemory(char* orig_ptr, size_t alignment, size_t or_mask) { 30 if ((alignment & (alignment - 1)) != 0) { 31 errx(1, "warning: alignment passed into GetAlignedMemory is not a power of two."); 32 } 33 if (or_mask > alignment) { 34 errx(1, "warning: or_mask passed into GetAlignedMemory is too high."); 35 } 36 uintptr_t ptr = reinterpret_cast<uintptr_t>(orig_ptr); 37 if (alignment > 0) { 38 // When setting the alignment, set it to exactly the alignment chosen. 39 // The pointer returned will be guaranteed not to be aligned to anything 40 // more than that. 41 ptr += alignment - (ptr & (alignment - 1)); 42 ptr |= alignment | or_mask; 43 } 44 45 return reinterpret_cast<char*>(ptr); 46 } 47 48 char* GetAlignedPtr(std::vector<char>* buf, size_t alignment, size_t nbytes) { 49 buf->resize(nbytes + 3 * alignment); 50 return GetAlignedMemory(buf->data(), alignment, 0); 51 } 52 53 wchar_t* GetAlignedPtr(std::vector<wchar_t>* buf, size_t alignment, size_t nchars) { 54 buf->resize(nchars + ceil((3 * alignment) / sizeof(wchar_t))); 55 return reinterpret_cast<wchar_t*>(GetAlignedMemory(reinterpret_cast<char*>(buf->data()), 56 alignment, 0)); 57 } 58 59 char* GetAlignedPtrFilled(std::vector<char>* buf, size_t alignment, size_t nbytes, char fill_byte) { 60 char* buf_aligned = GetAlignedPtr(buf, alignment, nbytes); 61 memset(buf_aligned, fill_byte, nbytes); 62 return buf_aligned; 63 } 64 65 #if defined(__APPLE__) 66 67 // Darwin doesn't support this, so do nothing. 68 bool LockToCPU(int) { 69 return false; 70 } 71 72 #else 73 74 bool LockToCPU(long cpu_to_lock) { 75 cpu_set_t cpuset; 76 77 CPU_ZERO(&cpuset); 78 if (sched_getaffinity(0, sizeof(cpuset), &cpuset) != 0) { 79 perror("sched_getaffinity failed"); 80 return false; 81 } 82 83 if (cpu_to_lock < 0) { 84 // Lock to the last active core we find. 85 for (int i = 0; i < CPU_SETSIZE; i++) { 86 if (CPU_ISSET(i, &cpuset)) { 87 cpu_to_lock = i; 88 } 89 } 90 } else if (!CPU_ISSET(cpu_to_lock, &cpuset)) { 91 printf("Cpu %ld does not exist.\n", cpu_to_lock); 92 return false; 93 } 94 95 if (cpu_to_lock < 0) { 96 printf("Cannot find any valid cpu to lock.\n"); 97 return false; 98 } 99 100 CPU_ZERO(&cpuset); 101 CPU_SET(cpu_to_lock, &cpuset); 102 if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) { 103 perror("sched_setaffinity failed"); 104 return false; 105 } 106 107 return true; 108 } 109 110 #endif 111
