xref: /libuv/test/benchmark-fs-stat.c (revision cb5da592)
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14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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19  * IN THE SOFTWARE.
20  */
21 
22 #include "task.h"
23 #include "uv.h"
24 
25 #include <stdio.h>
26 #include <stdlib.h>
27 
28 #define NUM_SYNC_REQS         (10 * 1e5)
29 #define NUM_ASYNC_REQS        (1 * (int) 1e5)
30 #define MAX_CONCURRENT_REQS   32
31 
32 #define sync_stat(req, path)                                                  \
33   do {                                                                        \
34     uv_fs_stat(NULL, (req), (path), NULL);                                    \
35     uv_fs_req_cleanup((req));                                                 \
36   }                                                                           \
37   while (0)
38 
39 struct async_req {
40   const char* path;
41   uv_fs_t fs_req;
42   int* count;
43 };
44 
45 
warmup(const char * path)46 static void warmup(const char* path) {
47   uv_fs_t reqs[MAX_CONCURRENT_REQS];
48   unsigned int i;
49 
50   /* warm up the thread pool */
51   for (i = 0; i < ARRAY_SIZE(reqs); i++)
52     uv_fs_stat(uv_default_loop(), reqs + i, path, uv_fs_req_cleanup);
53 
54   uv_run(uv_default_loop(), UV_RUN_DEFAULT);
55 
56   /* warm up the OS dirent cache */
57   for (i = 0; i < 16; i++)
58     sync_stat(reqs + 0, path);
59 }
60 
61 
sync_bench(const char * path)62 static void sync_bench(const char* path) {
63   char fmtbuf[2][32];
64   uint64_t before;
65   uint64_t after;
66   uv_fs_t req;
67   int i;
68 
69   /* do the sync benchmark */
70   before = uv_hrtime();
71 
72   for (i = 0; i < NUM_SYNC_REQS; i++)
73     sync_stat(&req, path);
74 
75   after = uv_hrtime();
76 
77   printf("%s stats (sync): %.2fs (%s/s)\n",
78          fmt(&fmtbuf[0], 1.0 * NUM_SYNC_REQS),
79          (after - before) / 1e9,
80          fmt(&fmtbuf[1], (1.0 * NUM_SYNC_REQS) / ((after - before) / 1e9)));
81   fflush(stdout);
82 }
83 
84 
stat_cb(uv_fs_t * fs_req)85 static void stat_cb(uv_fs_t* fs_req) {
86   struct async_req* req = container_of(fs_req, struct async_req, fs_req);
87   uv_fs_req_cleanup(&req->fs_req);
88   if (*req->count == 0) return;
89   uv_fs_stat(uv_default_loop(), &req->fs_req, req->path, stat_cb);
90   (*req->count)--;
91 }
92 
93 
async_bench(const char * path)94 static void async_bench(const char* path) {
95   struct async_req reqs[MAX_CONCURRENT_REQS];
96   struct async_req* req;
97   char fmtbuf[2][32];
98   uint64_t before;
99   uint64_t after;
100   int count;
101   int i;
102 
103   for (i = 1; i <= MAX_CONCURRENT_REQS; i++) {
104     count = NUM_ASYNC_REQS;
105 
106     for (req = reqs; req < reqs + i; req++) {
107       req->path = path;
108       req->count = &count;
109       uv_fs_stat(uv_default_loop(), &req->fs_req, req->path, stat_cb);
110     }
111 
112     before = uv_hrtime();
113     uv_run(uv_default_loop(), UV_RUN_DEFAULT);
114     after = uv_hrtime();
115 
116     printf("%s stats (%d concurrent): %.2fs (%s/s)\n",
117            fmt(&fmtbuf[0], 1.0 * NUM_ASYNC_REQS),
118            i,
119            (after - before) / 1e9,
120            fmt(&fmtbuf[1], (1.0 * NUM_ASYNC_REQS) / ((after - before) / 1e9)));
121     fflush(stdout);
122   }
123 }
124 
125 
126 /* This benchmark aims to measure the overhead of doing I/O syscalls from
127  * the thread pool. The stat() syscall was chosen because its results are
128  * easy for the operating system to cache, taking the actual I/O overhead
129  * out of the equation.
130  */
BENCHMARK_IMPL(fs_stat)131 BENCHMARK_IMPL(fs_stat) {
132   const char path[] = ".";
133   warmup(path);
134   sync_bench(path);
135   async_bench(path);
136   MAKE_VALGRIND_HAPPY(uv_default_loop());
137   return 0;
138 }
139