From: "Jeff Hostetler via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: gitster@pobox.com, peff@peff.net, jrnieder@gmail.com,
steadmon@google.com, avarab@gmail.com,
Junio C Hamano <gitster@pobox.com>,
Jeff Hostetler <jeffhost@microsoft.com>
Subject: [PATCH v3 02/10] trace2: refactor setting process starting time
Date: Thu, 11 Apr 2019 08:18:39 -0700 (PDT) [thread overview]
Message-ID: <3dbcfc6a8dce98dfec502c4b2a090450c9f9c66b.1554995916.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.169.v3.git.gitgitgadget@gmail.com>
From: Jeff Hostetler <jeffhost@microsoft.com>
Create trace2_initialize_clock() and call from main() to capture
process start time in isolation and before other sub-systems are
ready.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
---
Documentation/technical/api-trace2.txt | 12 ++++++--
common-main.c | 2 ++
compat/mingw.c | 2 ++
trace2.c | 7 ++++-
trace2.h | 17 ++++++++++++
trace2/tr2_tls.c | 38 ++++++++++++++++----------
trace2/tr2_tls.h | 8 +++++-
7 files changed, 67 insertions(+), 19 deletions(-)
diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt
index 2de565fa3d..f37fccf1da 100644
--- a/Documentation/technical/api-trace2.txt
+++ b/Documentation/technical/api-trace2.txt
@@ -160,17 +160,23 @@ purposes.
These are concerned with the lifetime of the overall git process.
+`void trace2_initialize_clock()`::
+
+ Initialize the Trace2 start clock and nothing else. This should
+ be called at the very top of main() to capture the process start
+ time and reduce startup order dependencies.
+
`void trace2_initialize()`::
Determines if any Trace2 Targets should be enabled and
- initializes the Trace2 facility. This includes starting the
- elapsed time clocks and thread local storage (TLS).
+ initializes the Trace2 facility. This includes setting up the
+ Trace2 thread local storage (TLS).
+
This function emits a "version" message containing the version of git
and the Trace2 protocol.
+
This function should be called from `main()` as early as possible in
-the life of the process.
+the life of the process after essential process initialization.
`int trace2_is_enabled()`::
diff --git a/common-main.c b/common-main.c
index d484aec209..6137af0e63 100644
--- a/common-main.c
+++ b/common-main.c
@@ -27,6 +27,8 @@ int main(int argc, const char **argv)
{
int result;
+ trace2_initialize_clock();
+
/*
* Always open file descriptors 0/1/2 to avoid clobbering files
* in die(). It also avoids messing up when the pipes are dup'ed
diff --git a/compat/mingw.c b/compat/mingw.c
index 6b04514cdc..a2f74aca6a 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2569,6 +2569,8 @@ void mingw_startup(void)
wchar_t **wenv, **wargv;
_startupinfo si;
+ trace2_initialize_clock();
+
maybe_redirect_std_handles();
/* get wide char arguments and environment */
diff --git a/trace2.c b/trace2.c
index ccccd4ef09..6dd51e6aa5 100644
--- a/trace2.c
+++ b/trace2.c
@@ -142,6 +142,11 @@ static void tr2main_signal_handler(int signo)
raise(signo);
}
+void trace2_initialize_clock(void)
+{
+ tr2tls_start_process_clock();
+}
+
void trace2_initialize_fl(const char *file, int line)
{
struct tr2_tgt *tgt_j;
@@ -428,7 +433,7 @@ void trace2_thread_start_fl(const char *file, int line, const char *thread_name)
us_now = getnanotime() / 1000;
us_elapsed_absolute = tr2tls_absolute_elapsed(us_now);
- tr2tls_create_self(thread_name);
+ tr2tls_create_self(thread_name, us_now);
for_each_wanted_builtin (j, tgt_j)
if (tgt_j->pfn_thread_start_fl)
diff --git a/trace2.h b/trace2.h
index ae5020d0e6..8f89e70c44 100644
--- a/trace2.h
+++ b/trace2.h
@@ -19,6 +19,23 @@ struct json_writer;
* [] trace2_printf* -- legacy trace[1] messages.
*/
+/*
+ * Initialize the TRACE2 clock and do nothing else, in particular
+ * no mallocs, no system inspection, and no environment inspection.
+ *
+ * This should be called at the very top of main() to capture the
+ * process start time. This is intended to reduce chicken-n-egg
+ * bootstrap pressure.
+ *
+ * It is safe to call this more than once. This allows capturing
+ * absolute startup costs on Windows which uses a little trickery
+ * to do setup work before common-main.c:main() is called.
+ *
+ * The main trace2_initialize_fl() may be called a little later
+ * after more infrastructure is established.
+ */
+void trace2_initialize_clock(void);
+
/*
* Initialize TRACE2 tracing facility if any of the builtin TRACE2
* targets are enabled in the environment. Emits a 'version' event.
diff --git a/trace2/tr2_tls.c b/trace2/tr2_tls.c
index 8e65b0361d..31fb529f93 100644
--- a/trace2/tr2_tls.c
+++ b/trace2/tr2_tls.c
@@ -10,16 +10,30 @@
#define TR2_REGION_NESTING_INITIAL_SIZE (100)
static struct tr2tls_thread_ctx *tr2tls_thread_main;
-static uint64_t tr2tls_us_start_main;
+static uint64_t tr2tls_us_start_process;
static pthread_mutex_t tr2tls_mutex;
static pthread_key_t tr2tls_key;
static int tr2_next_thread_id; /* modify under lock */
-struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name)
+void tr2tls_start_process_clock(void)
+{
+ if (tr2tls_us_start_process)
+ return;
+
+ /*
+ * Keep the absolute start time of the process (i.e. the main
+ * process) in a fixed variable since other threads need to
+ * access it. This allows them to do that without a lock on
+ * main thread's array data (because of reallocs).
+ */
+ tr2tls_us_start_process = getnanotime() / 1000;
+}
+
+struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name,
+ uint64_t us_thread_start)
{
- uint64_t us_now = getnanotime() / 1000;
struct tr2tls_thread_ctx *ctx = xcalloc(1, sizeof(*ctx));
/*
@@ -29,7 +43,7 @@ struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name)
*/
ctx->alloc = TR2_REGION_NESTING_INITIAL_SIZE;
ctx->array_us_start = (uint64_t *)xcalloc(ctx->alloc, sizeof(uint64_t));
- ctx->array_us_start[ctx->nr_open_regions++] = us_now;
+ ctx->array_us_start[ctx->nr_open_regions++] = us_thread_start;
ctx->thread_id = tr2tls_locked_increment(&tr2_next_thread_id);
@@ -55,7 +69,7 @@ struct tr2tls_thread_ctx *tr2tls_get_self(void)
* here and silently continue.
*/
if (!ctx)
- ctx = tr2tls_create_self("unknown");
+ ctx = tr2tls_create_self("unknown", getnanotime() / 1000);
return ctx;
}
@@ -124,22 +138,18 @@ uint64_t tr2tls_absolute_elapsed(uint64_t us)
if (!tr2tls_thread_main)
return 0;
- return us - tr2tls_us_start_main;
+ return us - tr2tls_us_start_process;
}
void tr2tls_init(void)
{
+ tr2tls_start_process_clock();
+
pthread_key_create(&tr2tls_key, NULL);
init_recursive_mutex(&tr2tls_mutex);
- tr2tls_thread_main = tr2tls_create_self("main");
- /*
- * Keep a copy of the absolute start time of the main thread
- * in a fixed variable since other threads need to access it.
- * This also eliminates the need to lock accesses to the main
- * thread's array (because of reallocs).
- */
- tr2tls_us_start_main = tr2tls_thread_main->array_us_start[0];
+ tr2tls_thread_main = tr2tls_create_self("main",
+ tr2tls_us_start_process);
}
void tr2tls_release(void)
diff --git a/trace2/tr2_tls.h b/trace2/tr2_tls.h
index bb80e3f8e7..b1e327a928 100644
--- a/trace2/tr2_tls.h
+++ b/trace2/tr2_tls.h
@@ -31,7 +31,8 @@ struct tr2tls_thread_ctx {
* In this and all following functions the term "self" refers to the
* current thread.
*/
-struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name);
+struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name,
+ uint64_t us_thread_start);
/*
* Get our TLS data.
@@ -94,4 +95,9 @@ void tr2tls_release(void);
*/
int tr2tls_locked_increment(int *p);
+/*
+ * Capture the process start time and do nothing else.
+ */
+void tr2tls_start_process_clock(void);
+
#endif /* TR2_TLS_H */
--
gitgitgadget
next prev parent reply other threads:[~2019-04-11 15:18 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-28 13:30 [PATCH 0/4] trace2: load trace2 settings from system config Jeff Hostetler via GitGitGadget
2019-03-28 13:30 ` [PATCH 1/4] trace2: refactor setting process starting time Jeff Hostetler via GitGitGadget
2019-03-28 13:31 ` [PATCH 2/4] trace2: add absolute elapsed time to start event Jeff Hostetler via GitGitGadget
2019-03-28 13:31 ` [PATCH 3/4] trace2: find exec-dir before trace2 initialization Jeff Hostetler via GitGitGadget
2019-03-28 13:31 ` [PATCH 4/4] trace2: use system config for default trace2 settings Jeff Hostetler via GitGitGadget
2019-03-28 14:36 ` Ævar Arnfjörð Bjarmason
2019-03-28 18:50 ` Jeff Hostetler
2019-03-28 21:28 ` Josh Steadmon
2019-03-29 17:04 ` [PATCH v2 0/7] trace2: load trace2 settings from system config Jeff Hostetler via GitGitGadget
2019-03-29 17:04 ` [PATCH v2 1/7] trace2: refactor setting process starting time Jeff Hostetler via GitGitGadget
2019-03-29 17:04 ` [PATCH v2 2/7] trace2: add absolute elapsed time to start event Jeff Hostetler via GitGitGadget
2019-03-29 17:04 ` [PATCH v2 3/7] trace2: find exec-dir before trace2 initialization Jeff Hostetler via GitGitGadget
2019-03-29 17:04 ` [PATCH v2 4/7] trace2: use system config for default trace2 settings Jeff Hostetler via GitGitGadget
2019-04-01 21:00 ` Josh Steadmon
2019-04-01 21:06 ` Jeff Hostetler
2019-04-03 0:01 ` Jonathan Nieder
2019-04-03 0:00 ` Jonathan Nieder
2019-04-09 15:58 ` Jeff Hostetler
2019-03-29 17:04 ` [PATCH v2 5/7] trace2: report peak memory usage of the process Jeff Hostetler via GitGitGadget
2019-03-29 22:16 ` Ævar Arnfjörð Bjarmason
2019-04-01 21:05 ` Jeff Hostetler
2019-03-29 17:04 ` [PATCH v2 7/7] trace2: make SIDs more unique Jeff Hostetler via GitGitGadget
2019-03-29 22:12 ` Ævar Arnfjörð Bjarmason
2019-04-01 21:16 ` Jeff Hostetler
2019-03-29 17:04 ` [PATCH v2 6/7] trace2: clarify UTC datetime formatting Jeff Hostetler via GitGitGadget
2019-04-01 21:02 ` [PATCH v2 0/7] trace2: load trace2 settings from system config Josh Steadmon
2019-04-11 15:18 ` [PATCH v3 00/10] " Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 01/10] config: initialize opts structure in repo_read_config() Jeff Hostetler via GitGitGadget
2019-04-12 3:52 ` Jonathan Nieder
2019-04-15 14:34 ` Johannes Schindelin
2019-04-11 15:18 ` Jeff Hostetler via GitGitGadget [this message]
2019-04-11 15:18 ` [PATCH v3 03/10] trace2: add absolute elapsed time to start event Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 04/10] trace2: find exec-dir before trace2 initialization Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 05/10] config: add read_very_early_config() Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 06/10] trace2: use system/global config for default trace2 settings Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 07/10] trace2: report peak memory usage of the process Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 08/10] trace2: clarify UTC datetime formatting Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 10/10] trace2: update docs to describe system/global config settings Jeff Hostetler via GitGitGadget
2019-04-11 15:18 ` [PATCH v3 09/10] trace2: make SIDs more unique Jeff Hostetler via GitGitGadget
2019-04-12 2:29 ` [PATCH v3 00/10] trace2: load trace2 settings from system config Junio C Hamano
2019-04-12 13:47 ` Jeff Hostetler
2019-04-15 20:39 ` [PATCH v4 " Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 01/10] config: initialize opts structure in repo_read_config() Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 02/10] trace2: refactor setting process starting time Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 03/10] trace2: add absolute elapsed time to start event Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 04/10] trace2: find exec-dir before trace2 initialization Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 05/10] config: add read_very_early_config() Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 06/10] trace2: use system/global config for default trace2 settings Jeff Hostetler via GitGitGadget
2019-04-27 13:43 ` SZEDER Gábor
2019-04-29 19:03 ` Jeff Hostetler
2019-04-15 20:39 ` [PATCH v4 08/10] trace2: clarify UTC datetime formatting Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 07/10] trace2: report peak memory usage of the process Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 09/10] trace2: make SIDs more unique Jeff Hostetler via GitGitGadget
2019-04-15 20:39 ` [PATCH v4 10/10] trace2: update docs to describe system/global config settings Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 00/11] trace2: load trace2 settings from system config Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 02/11] trace2: refactor setting process starting time Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 01/11] config: initialize opts structure in repo_read_config() Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 03/11] trace2: add absolute elapsed time to start event Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 04/11] trace2: find exec-dir before trace2 initialization Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 05/11] config: add read_very_early_config() Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 06/11] trace2: use system/global config for default trace2 settings Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 07/11] trace2: report peak memory usage of the process Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 09/11] trace2: make SIDs more unique Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 08/11] trace2: clarify UTC datetime formatting Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 10/11] trace2: update docs to describe system/global config settings Jeff Hostetler via GitGitGadget
2019-04-29 20:14 ` [PATCH v5 11/11] trace2: fixup access problem on /etc/gitconfig in read_very_early_config Jeff Hostetler via GitGitGadget
2019-04-29 20:21 ` [PATCH v5 00/11] trace2: load trace2 settings from system config Jeff Hostetler
2019-05-07 1:18 ` Junio C Hamano
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