| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2016 Red Hat, Inc. |
| 3 | * Author: Michael S. Tsirkin <mst@redhat.com> |
| 4 | * This work is licensed under the terms of the GNU GPL, version 2. |
| 5 | * |
| 6 | * Common macros and functions for ring benchmarking. |
| 7 | */ |
| 8 | #ifndef MAIN_H |
| 9 | #define MAIN_H |
| 10 | |
| 11 | #include <stdbool.h> |
| 12 | |
| 13 | extern int param; |
| 14 | |
| 15 | extern bool do_exit; |
| 16 | |
| 17 | #if defined(__x86_64__) || defined(__i386__) |
| 18 | #include "x86intrin.h" |
| 19 | |
| 20 | static inline void wait_cycles(unsigned long long cycles) |
| 21 | { |
| 22 | unsigned long long t; |
| 23 | |
| 24 | t = __rdtsc(); |
| 25 | while (__rdtsc() - t < cycles) {} |
| 26 | } |
| 27 | |
| 28 | #define VMEXIT_CYCLES 500 |
| 29 | #define VMENTRY_CYCLES 500 |
| 30 | |
| 31 | #elif defined(__s390x__) |
| 32 | static inline void wait_cycles(unsigned long long cycles) |
| 33 | { |
| 34 | asm volatile("0: brctg %0,0b" : : "d" (cycles)); |
| 35 | } |
| 36 | |
| 37 | /* tweak me */ |
| 38 | #define VMEXIT_CYCLES 200 |
| 39 | #define VMENTRY_CYCLES 200 |
| 40 | |
| 41 | #else |
| 42 | static inline void wait_cycles(unsigned long long cycles) |
| 43 | { |
| 44 | _Exit(5); |
| 45 | } |
| 46 | #define VMEXIT_CYCLES 0 |
| 47 | #define VMENTRY_CYCLES 0 |
| 48 | #endif |
| 49 | |
| 50 | static inline void vmexit(void) |
| 51 | { |
| 52 | if (!do_exit) |
| 53 | return; |
| 54 | |
| 55 | wait_cycles(VMEXIT_CYCLES); |
| 56 | } |
| 57 | static inline void vmentry(void) |
| 58 | { |
| 59 | if (!do_exit) |
| 60 | return; |
| 61 | |
| 62 | wait_cycles(VMENTRY_CYCLES); |
| 63 | } |
| 64 | |
| 65 | /* implemented by ring */ |
| 66 | void alloc_ring(void); |
| 67 | /* guest side */ |
| 68 | int add_inbuf(unsigned, void *, void *); |
| 69 | void *get_buf(unsigned *, void **); |
| 70 | void disable_call(); |
| 71 | bool used_empty(); |
| 72 | bool enable_call(); |
| 73 | void kick_available(); |
| 74 | /* host side */ |
| 75 | void disable_kick(); |
| 76 | bool avail_empty(); |
| 77 | bool enable_kick(); |
| 78 | bool use_buf(unsigned *, void **); |
| 79 | void call_used(); |
| 80 | |
| 81 | /* implemented by main */ |
| 82 | extern bool do_sleep; |
| 83 | void kick(void); |
| 84 | void wait_for_kick(void); |
| 85 | void call(void); |
| 86 | void wait_for_call(void); |
| 87 | |
| 88 | extern unsigned ring_size; |
| 89 | |
| 90 | /* Compiler barrier - similar to what Linux uses */ |
| 91 | #define barrier() asm volatile("" ::: "memory") |
| 92 | |
| 93 | /* Is there a portable way to do this? */ |
| 94 | #if defined(__x86_64__) || defined(__i386__) |
| 95 | #define cpu_relax() asm ("rep; nop" ::: "memory") |
| 96 | #elif defined(__s390x__) |
| 97 | #define cpu_relax() barrier() |
| 98 | #else |
| 99 | #define cpu_relax() assert(0) |
| 100 | #endif |
| 101 | |
| 102 | extern bool do_relax; |
| 103 | |
| 104 | static inline void busy_wait(void) |
| 105 | { |
| 106 | if (do_relax) |
| 107 | cpu_relax(); |
| 108 | else |
| 109 | /* prevent compiler from removing busy loops */ |
| 110 | barrier(); |
| 111 | } |
| 112 | |
| 113 | /* |
| 114 | * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized |
| 115 | * with other __ATOMIC_SEQ_CST calls. |
| 116 | */ |
| 117 | #define smp_mb() __sync_synchronize() |
| 118 | |
| 119 | /* |
| 120 | * This abuses the atomic builtins for thread fences, and |
| 121 | * adds a compiler barrier. |
| 122 | */ |
| 123 | #define smp_release() do { \ |
| 124 | barrier(); \ |
| 125 | __atomic_thread_fence(__ATOMIC_RELEASE); \ |
| 126 | } while (0) |
| 127 | |
| 128 | #define smp_acquire() do { \ |
| 129 | __atomic_thread_fence(__ATOMIC_ACQUIRE); \ |
| 130 | barrier(); \ |
| 131 | } while (0) |
| 132 | |
| 133 | #endif |