From: Derrick Stolee <stolee@gmail.com>
To: Jeff Hostetler via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org
Cc: Jeff Hostetler <jeffhost@microsoft.com>
Subject: Re: [PATCH 6/9] trace2: add timer events to perf and event target formats
Date: Tue, 21 Dec 2021 09:20:26 -0500 [thread overview]
Message-ID: <8f62bae5-0026-c2c8-baa0-fd50b8d1668c@gmail.com> (raw)
In-Reply-To: <c5d5ff05e6ca5729993133ce0b6b94af2503808a.1640012469.git.gitgitgadget@gmail.com>
On 12/20/2021 10:01 AM, Jeff Hostetler via GitGitGadget wrote:
> +`"timer"`::
> + This event is generated at the end of the program and contains
> + statistics for a global stopwatch timer.
> ++
> +------------
> +{
> + "event":"timer",
> + ...
> + "name":"test", # timer name
> + "count":42, # number of start+stop intervals
> + "t_total":1.234, # sum of all intervals (by thread or globally)
> + "t_min":0.1, # shortest interval
> + "t_max":0.9, # longest interval
Could you specify the units for these t_* entries? I'm guessing seconds
based on the example, but I've seen similar timers using milliseconds
instead so it's best to be super clear here.
> +/*
> + * Stopwatch timer event. This function writes the previously accumlated
s/accumlated/accumulated/
> + * stopwatch timer values to the event streams. Unlike other Trace2 API
> + * events, this is decoupled from the data collection.
> + *
> + * This does not take a (file,line) pair because a timer event reports
> + * the cummulative time spend in the timer over a series of intervals
s/cummulative/cumulative/
> + * -- it does not represent a single usage (like region or data events
> + * do).
> + *
> + * The thread name is optional. If non-null it will override the
> + * value inherited from the caller's TLS CTX. This allows data
> + * for global timers to be reported without associating it with a
> + * single thread.
> + */
> +typedef void(tr2_tgt_evt_timer_t)(uint64_t us_elapsed_absolute,
> + const char *thread_name,
> + const char *category,
> + const char *timer_name,
> + uint64_t interval_count,
> + uint64_t us_total_time,
> + uint64_t us_min_time,
> + uint64_t us_max_time);
> diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c
> index 4ce50944298..9b3905b920c 100644
> --- a/trace2/tr2_tgt_event.c
> +++ b/trace2/tr2_tgt_event.c
...
> +static void fn_timer(uint64_t us_elapsed_absolute,
(I was going to complain about the generic name here, but it's static
to the tr2_tgt_event.c file, so that's fine.)
> + const char *thread_name,
> + const char *category,
> + const char *timer_name,
> + uint64_t interval_count,
> + uint64_t us_total_time,
> + uint64_t us_min_time,
> + uint64_t us_max_time)
> +{
> + const char *event_name = "timer";
> + struct json_writer jw = JSON_WRITER_INIT;
> + double t_abs = (double)us_elapsed_absolute / 1000000.0;
> +
> + double t_total = (double)us_total_time / 1000000.0;
> + double t_min = (double)us_min_time / 1000000.0;
> + double t_max = (double)us_max_time / 1000000.0;
Looks like seconds here. At first glance, I thought this large division
might cause some loss of precision. However, the structure of floating
point numbers means we probably don't lose that much. It might be worth
_considering_ using milliseconds (only divide by 1000.0) but I'm
probably just being paranoid here.
Thanks,
-Stolee
next prev parent reply other threads:[~2021-12-21 14:20 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-20 15:01 [PATCH 0/9] Trace2 stopwatch timers and global counters Jeff Hostetler via GitGitGadget
2021-12-20 15:01 ` [PATCH 1/9] trace2: use size_t alloc,nr_open_regions in tr2tls_thread_ctx Jeff Hostetler via GitGitGadget
2021-12-20 15:01 ` [PATCH 2/9] trace2: convert tr2tls_thread_ctx.thread_name from strbuf to char* Jeff Hostetler via GitGitGadget
2021-12-20 16:31 ` Ævar Arnfjörð Bjarmason
2021-12-20 19:07 ` Jeff Hostetler
2021-12-20 19:35 ` Ævar Arnfjörð Bjarmason
2021-12-22 16:32 ` Jeff Hostetler
2021-12-21 7:33 ` Junio C Hamano
2021-12-21 7:22 ` Junio C Hamano
2021-12-22 16:28 ` Jeff Hostetler
2021-12-22 19:57 ` Junio C Hamano
2021-12-20 15:01 ` [PATCH 3/9] trace2: defer free of TLS CTX until program exit Jeff Hostetler via GitGitGadget
2021-12-21 7:30 ` Junio C Hamano
2021-12-22 21:59 ` Jeff Hostetler
2021-12-22 22:56 ` Junio C Hamano
2021-12-22 23:04 ` Jeff Hostetler
2021-12-23 7:38 ` Johannes Sixt
2021-12-23 18:18 ` Junio C Hamano
2021-12-27 18:51 ` Jeff Hostetler
2021-12-20 15:01 ` [PATCH 4/9] trace2: add thread-name override to event target Jeff Hostetler via GitGitGadget
2021-12-20 15:01 ` [PATCH 5/9] trace2: add thread-name override to perf target Jeff Hostetler via GitGitGadget
2021-12-20 15:01 ` [PATCH 6/9] trace2: add timer events to perf and event target formats Jeff Hostetler via GitGitGadget
2021-12-20 16:39 ` Ævar Arnfjörð Bjarmason
2021-12-20 19:44 ` Jeff Hostetler
2021-12-21 14:20 ` Derrick Stolee [this message]
2021-12-20 15:01 ` [PATCH 7/9] trace2: add stopwatch timers Jeff Hostetler via GitGitGadget
2021-12-20 16:42 ` Ævar Arnfjörð Bjarmason
2021-12-22 21:38 ` Jeff Hostetler
2021-12-21 14:45 ` Derrick Stolee
2021-12-22 21:57 ` Jeff Hostetler
2021-12-20 15:01 ` [PATCH 8/9] trace2: add counter events to perf and event target formats Jeff Hostetler via GitGitGadget
2021-12-20 16:51 ` Ævar Arnfjörð Bjarmason
2021-12-22 22:56 ` Jeff Hostetler
2021-12-20 15:01 ` [PATCH 9/9] trace2: add global counters Jeff Hostetler via GitGitGadget
2021-12-20 17:14 ` Ævar Arnfjörð Bjarmason
2021-12-22 22:18 ` Jeff Hostetler
2021-12-21 14:51 ` [PATCH 0/9] Trace2 stopwatch timers and " Derrick Stolee
2021-12-21 23:27 ` Matheus Tavares
2021-12-28 19:36 ` [PATCH v2 " Jeff Hostetler via GitGitGadget
2021-12-28 19:36 ` [PATCH v2 1/9] trace2: use size_t alloc,nr_open_regions in tr2tls_thread_ctx Jeff Hostetler via GitGitGadget
2021-12-29 0:48 ` Ævar Arnfjörð Bjarmason
2021-12-28 19:36 ` [PATCH v2 2/9] trace2: convert tr2tls_thread_ctx.thread_name from strbuf to flex array Jeff Hostetler via GitGitGadget
2021-12-29 1:11 ` Ævar Arnfjörð Bjarmason
2021-12-29 16:46 ` Jeff Hostetler
2021-12-28 19:36 ` [PATCH v2 3/9] trace2: defer free of thread local storage until program exit Jeff Hostetler via GitGitGadget
2021-12-28 19:36 ` [PATCH v2 4/9] trace2: add thread-name override to event target Jeff Hostetler via GitGitGadget
2021-12-28 19:36 ` [PATCH v2 5/9] trace2: add thread-name override to perf target Jeff Hostetler via GitGitGadget
2021-12-29 1:48 ` Ævar Arnfjörð Bjarmason
2021-12-29 17:15 ` Jeff Hostetler
2021-12-28 19:36 ` [PATCH v2 6/9] trace2: add timer events to perf and event target formats Jeff Hostetler via GitGitGadget
2021-12-28 19:36 ` [PATCH v2 7/9] trace2: add stopwatch timers Jeff Hostetler via GitGitGadget
2021-12-28 19:36 ` [PATCH v2 8/9] trace2: add counter events to perf and event target formats Jeff Hostetler via GitGitGadget
2021-12-28 19:36 ` [PATCH v2 9/9] trace2: add global counters Jeff Hostetler via GitGitGadget
2021-12-29 1:54 ` [PATCH v2 0/9] Trace2 stopwatch timers and " Ævar Arnfjörð Bjarmason
2021-12-30 16:42 ` Jeff Hostetler
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