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 v4 02/10] trace2: refactor setting process starting time Date: Mon, 15 Apr 2019 13:39:43 -0700 (PDT) Message-ID: <48e34834b6a65b9f2c68d4f4e459586b2948b6cd.1555360780.git.gitgitgadget@gmail.com> (raw) In-Reply-To: <pull.169.v4.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..e76d8c5d92 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:[~2019-04-15 20:39 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 6/7] trace2: clarify UTC datetime formatting Jeff Hostetler via GitGitGadget 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 2019-04-01 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 ` [PATCH v3 02/10] trace2: refactor setting process starting time Jeff Hostetler via GitGitGadget 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 09/10] trace2: make SIDs more unique 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 2019-04-12 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 ` Jeff Hostetler via GitGitGadget [this message] 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 07/10] trace2: report peak memory usage of the process Jeff Hostetler via GitGitGadget 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 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 01/11] config: initialize opts structure in repo_read_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 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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