trace: improve trace performance
The trace API currently rechecks the environment variable and reopens the trace file on every API call. This has the ugly side effect that errors (e.g. file cannot be opened, or the user specified a relative path) are also reported on every call. Performance can be improved by about factor three by remembering the environment state and keeping the file open. Replace the 'const char *key' parameter in the API with a pointer to a 'struct trace_key' that bundles the environment variable name with additional, trace-internal state. Change the call sites of these APIs to use a static 'struct trace_key' instead of a string constant. In trace.c::get_trace_fd(), save and reuse the file descriptor in 'struct trace_key'. Add a 'trace_disable()' API, so that packet_trace() can cleanly disable tracing when it encounters packed data (instead of using unsetenv()). Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Karsten Blees committed
Jul 12, 2014 at 02:00 UTC
6aa3085702cc7a436c12f4c4396958281df1da44
6 files changed
+78
-59
builtin/receive-pack.c
+1
-1
@@ -438,7 +438,7 @@ static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
438
uint32_t mask = 1 << (cmd->index % 32);
439
int i;
440
441
- trace_printf_key("GIT_TRACE_SHALLOW",
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+ trace_printf_key(&trace_shallow,
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"shallow: update_shallow_ref %s\n", cmd->ref_name);
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for (i = 0; i < si->shallow->nr; i++)
444
if (si->used_shallow[i] &&
commit.h
+1
@@ -235,6 +235,7 @@ extern void assign_shallow_commits_to_refs(struct shallow_info *info,
235
int *ref_status);
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extern int delayed_reachability_test(struct shallow_info *si, int c);
237
extern void prune_shallow(int show_only);
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+extern struct trace_key trace_shallow;
239
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int is_descendant_of(struct commit *, struct commit_list *);
241
int in_merge_bases(struct commit *, struct commit *);
pkt-line.c
+4
-4
@@ -3,7 +3,7 @@
3
4
char packet_buffer[LARGE_PACKET_MAX];
5
static const char *packet_trace_prefix = "git";
6
-static const char trace_key[] = "GIT_TRACE_PACKET";
6
+static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
7
8
void packet_trace_identity(const char *prog)
9
{
@@ -15,7 +15,7 @@ static void packet_trace(const char *buf, unsigned int len, int write)
15
int i;
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struct strbuf out;
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- if (!trace_want(trace_key))
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+ if (!trace_want(&trace_packet))
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return;
20
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/* +32 is just a guess for header + quoting */
@@ -27,7 +27,7 @@ static void packet_trace(const char *buf, unsigned int len, int write)
27
if ((len >= 4 && starts_with(buf, "PACK")) ||
28
(len >= 5 && starts_with(buf+1, "PACK"))) {
29
strbuf_addstr(&out, "PACK ...");
30
- unsetenv(trace_key);
30
+ trace_disable(&trace_packet);
31
}
32
else {
33
/* XXX we should really handle printable utf8 */
@@ -43,7 +43,7 @@ static void packet_trace(const char *buf, unsigned int len, int write)
43
}
44
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strbuf_addch(&out, '\n');
46
- trace_strbuf(trace_key, &out);
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+ trace_strbuf(&trace_packet, &out);
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strbuf_release(&out);
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}
49
shallow.c
+5
-5
@@ -325,7 +325,7 @@ void prune_shallow(int show_only)
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strbuf_release(&sb);
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}
327
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-#define TRACE_KEY "GIT_TRACE_SHALLOW"
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+struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
329
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/*
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* Step 1, split sender shallow commits into "ours" and "theirs"
@@ -334,7 +334,7 @@ void prune_shallow(int show_only)
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void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
335
{
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int i;
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- trace_printf_key(TRACE_KEY, "shallow: prepare_shallow_info\n");
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+ trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
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memset(info, 0, sizeof(*info));
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info->shallow = sa;
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if (!sa)
@@ -365,7 +365,7 @@ void remove_nonexistent_theirs_shallow(struct shallow_info *info)
365
{
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unsigned char (*sha1)[20] = info->shallow->sha1;
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int i, dst;
368
- trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_theirs_shallow\n");
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+ trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
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for (i = dst = 0; i < info->nr_theirs; i++) {
370
if (i != dst)
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info->theirs[dst] = info->theirs[i];
@@ -516,7 +516,7 @@ void assign_shallow_commits_to_refs(struct shallow_info *info,
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int *shallow, nr_shallow = 0;
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struct paint_info pi;
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519
- trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
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+ trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
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shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
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for (i = 0; i < info->nr_ours; i++)
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shallow[nr_shallow++] = info->ours[i];
@@ -622,7 +622,7 @@ static void post_assign_shallow(struct shallow_info *info,
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int bitmap_nr = (info->ref->nr + 31) / 32;
623
struct commit_array ca;
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- trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
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+ trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
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if (ref_status)
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memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
628
trace.c
+54
-46
@@ -26,43 +26,66 @@
26
#include "quote.h"
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/* Get a trace file descriptor from "key" env variable. */
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-static int get_trace_fd(const char *key, int *need_close)
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+static int get_trace_fd(struct trace_key *key)
30
{
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- char *trace = getenv(key);
31
+ static struct trace_key trace_default = { "GIT_TRACE" };
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+ const char *trace;
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+
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+ /* use default "GIT_TRACE" if NULL */
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+ if (!key)
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+ key = &trace_default;
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+
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+ /* don't open twice */
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+ if (key->initialized)
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+ return key->fd;
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+
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+ trace = getenv(key->key);
43
44
if (!trace || !strcmp(trace, "") ||
45
!strcmp(trace, "0") || !strcasecmp(trace, "false"))
35
- return 0;
36
- if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
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- return STDERR_FILENO;
38
- if (strlen(trace) == 1 && isdigit(*trace))
39
- return atoi(trace);
40
- if (is_absolute_path(trace)) {
46
+ key->fd = 0;
47
+ else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
48
+ key->fd = STDERR_FILENO;
49
+ else if (strlen(trace) == 1 && isdigit(*trace))
50
+ key->fd = atoi(trace);
51
+ else if (is_absolute_path(trace)) {
52
int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
53
if (fd == -1) {
54
fprintf(stderr,
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"Could not open '%s' for tracing: %s\n"
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"Defaulting to tracing on stderr...\n",
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trace, strerror(errno));
47
- return STDERR_FILENO;
58
+ key->fd = STDERR_FILENO;
59
+ } else {
60
+ key->fd = fd;
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+ key->need_close = 1;
62
}
49
- *need_close = 1;
50
- return fd;
63
+ } else {
64
+ fprintf(stderr, "What does '%s' for %s mean?\n"
65
+ "If you want to trace into a file, then please set "
66
+ "%s to an absolute pathname (starting with /).\n"
67
+ "Defaulting to tracing on stderr...\n",
68
+ trace, key->key, key->key);
69
+ key->fd = STDERR_FILENO;
70
}
71
53
- fprintf(stderr, "What does '%s' for %s mean?\n", trace, key);
54
- fprintf(stderr, "If you want to trace into a file, "
55
- "then please set %s to an absolute pathname "
56
- "(starting with /).\n", key);
57
- fprintf(stderr, "Defaulting to tracing on stderr...\n");
72
+ key->initialized = 1;
73
+ return key->fd;
74
+}
75
59
- return STDERR_FILENO;
76
+void trace_disable(struct trace_key *key)
77
+{
78
+ if (key->need_close)
79
+ close(key->fd);
80
+ key->fd = 0;
81
+ key->initialized = 1;
82
+ key->need_close = 0;
83
}
84
85
static const char err_msg[] = "Could not trace into fd given by "
86
"GIT_TRACE environment variable";
87
65
-static void trace_vprintf(const char *key, const char *format, va_list ap)
88
+static void trace_vprintf(struct trace_key *key, const char *format, va_list ap)
89
{
90
struct strbuf buf = STRBUF_INIT;
91
@@ -75,7 +98,7 @@ static void trace_vprintf(const char *key, const char *format, va_list ap)
98
strbuf_release(&buf);
99
}
100
78
-void trace_printf_key(const char *key, const char *format, ...)
101
+void trace_printf_key(struct trace_key *key, const char *format, ...)
102
{
103
va_list ap;
104
va_start(ap, format);
@@ -87,31 +110,24 @@ void trace_printf(const char *format, ...)
110
{
111
va_list ap;
112
va_start(ap, format);
90
- trace_vprintf("GIT_TRACE", format, ap);
113
+ trace_vprintf(NULL, format, ap);
114
va_end(ap);
115
}
116
94
-void trace_strbuf(const char *key, const struct strbuf *buf)
117
+void trace_strbuf(struct trace_key *key, const struct strbuf *buf)
118
{
96
- int fd, need_close = 0;
97
-
98
- fd = get_trace_fd(key, &need_close);
119
+ int fd = get_trace_fd(key);
120
if (!fd)
121
return;
122
123
write_or_whine_pipe(fd, buf->buf, buf->len, err_msg);
103
-
104
- if (need_close)
105
- close(fd);
124
}
125
126
void trace_argv_printf(const char **argv, const char *format, ...)
127
{
128
struct strbuf buf = STRBUF_INIT;
129
va_list ap;
112
- int fd, need_close = 0;
113
-
114
- fd = get_trace_fd("GIT_TRACE", &need_close);
130
+ int fd = get_trace_fd(NULL);
131
if (!fd)
132
return;
133
@@ -124,9 +140,6 @@ void trace_argv_printf(const char **argv, const char *format, ...)
140
strbuf_addch(&buf, '\n');
141
write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
142
strbuf_release(&buf);
127
-
128
- if (need_close)
129
- close(fd);
143
}
144
145
static const char *quote_crnl(const char *path)
@@ -155,11 +168,11 @@ static const char *quote_crnl(const char *path)
168
/* FIXME: move prefix to startup_info struct and get rid of this arg */
169
void trace_repo_setup(const char *prefix)
170
{
158
- static const char *key = "GIT_TRACE_SETUP";
171
+ static struct trace_key key = TRACE_KEY_INIT(SETUP);
172
const char *git_work_tree;
173
char cwd[PATH_MAX];
174
162
- if (!trace_want(key))
175
+ if (!trace_want(&key))
176
return;
177
178
if (!getcwd(cwd, PATH_MAX))
@@ -171,18 +184,13 @@ void trace_repo_setup(const char *prefix)
184
if (!prefix)
185
prefix = "(null)";
186
174
- trace_printf_key(key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
175
- trace_printf_key(key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
176
- trace_printf_key(key, "setup: cwd: %s\n", quote_crnl(cwd));
177
- trace_printf_key(key, "setup: prefix: %s\n", quote_crnl(prefix));
187
+ trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
188
+ trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
189
+ trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
190
+ trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
191
}
192
180
-int trace_want(const char *key)
193
+int trace_want(struct trace_key *key)
194
{
182
- const char *trace = getenv(key);
183
-
184
- if (!trace || !strcmp(trace, "") ||
185
- !strcmp(trace, "0") || !strcasecmp(trace, "false"))
186
- return 0;
187
- return 1;
195
+ return !!get_trace_fd(key);
196
}
trace.h
+13
-3
@@ -4,14 +4,24 @@
4
#include "git-compat-util.h"
5
#include "strbuf.h"
6
7
+struct trace_key {
8
+ const char * const key;
9
+ int fd;
10
+ unsigned int initialized : 1;
11
+ unsigned int need_close : 1;
12
+};
13
+
14
+#define TRACE_KEY_INIT(name) { "GIT_TRACE_" #name, 0, 0, 0 }
15
+
16
__attribute__((format (printf, 1, 2)))
17
extern void trace_printf(const char *format, ...);
18
__attribute__((format (printf, 2, 3)))
19
extern void trace_argv_printf(const char **argv, const char *format, ...);
20
extern void trace_repo_setup(const char *prefix);
12
-extern int trace_want(const char *key);
21
+extern int trace_want(struct trace_key *key);
22
+extern void trace_disable(struct trace_key *key);
23
__attribute__((format (printf, 2, 3)))
14
-extern void trace_printf_key(const char *key, const char *format, ...);
15
-extern void trace_strbuf(const char *key, const struct strbuf *buf);
24
+extern void trace_printf_key(struct trace_key *key, const char *format, ...);
25
+extern void trace_strbuf(struct trace_key *key, const struct strbuf *buf);
26
27
#endif /* TRACE_H */