1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 | /* * Copyright (C) 2016 Red Hat, Inc. * Author: Michael S. Tsirkin <mst@redhat.com> * This work is licensed under the terms of the GNU GPL, version 2. * * Common macros and functions for ring benchmarking. */ #ifndef MAIN_H #define MAIN_H #include <stdbool.h> extern bool do_exit; #if defined(__x86_64__) || defined(__i386__) #include "x86intrin.h" static inline void wait_cycles(unsigned long long cycles) { unsigned long long t; t = __rdtsc(); while (__rdtsc() - t < cycles) {} } #define VMEXIT_CYCLES 500 #define VMENTRY_CYCLES 500 #elif defined(__s390x__) static inline void wait_cycles(unsigned long long cycles) { asm volatile("0: brctg %0,0b" : : "d" (cycles)); } /* tweak me */ #define VMEXIT_CYCLES 200 #define VMENTRY_CYCLES 200 #else static inline void wait_cycles(unsigned long long cycles) { _Exit(5); } #define VMEXIT_CYCLES 0 #define VMENTRY_CYCLES 0 #endif static inline void vmexit(void) { if (!do_exit) return; wait_cycles(VMEXIT_CYCLES); } static inline void vmentry(void) { if (!do_exit) return; wait_cycles(VMENTRY_CYCLES); } /* implemented by ring */ void alloc_ring(void); /* guest side */ int add_inbuf(unsigned, void *, void *); void *get_buf(unsigned *, void **); void disable_call(); bool used_empty(); bool enable_call(); void kick_available(); /* host side */ void disable_kick(); bool avail_empty(); bool enable_kick(); bool use_buf(unsigned *, void **); void call_used(); /* implemented by main */ extern bool do_sleep; void kick(void); void wait_for_kick(void); void call(void); void wait_for_call(void); extern unsigned ring_size; /* Compiler barrier - similar to what Linux uses */ #define barrier() asm volatile("" ::: "memory") /* Is there a portable way to do this? */ #if defined(__x86_64__) || defined(__i386__) #define cpu_relax() asm ("rep; nop" ::: "memory") #elif defined(__s390x__) #define cpu_relax() barrier() #else #define cpu_relax() assert(0) #endif extern bool do_relax; static inline void busy_wait(void) { if (do_relax) cpu_relax(); else /* prevent compiler from removing busy loops */ barrier(); } /* * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized * with other __ATOMIC_SEQ_CST calls. */ #define smp_mb() __sync_synchronize() /* * This abuses the atomic builtins for thread fences, and * adds a compiler barrier. */ #define smp_release() do { \ barrier(); \ __atomic_thread_fence(__ATOMIC_RELEASE); \ } while (0) #define smp_acquire() do { \ __atomic_thread_fence(__ATOMIC_ACQUIRE); \ barrier(); \ } while (0) #endif |