Since 81071626ba (trace2: add global counter mechanism, 2022-10-24)
these tests have been failing when git is compiled with NO_PTHREADS=Y,
which is always the case e.g. if 'uname -s' is "NONSTOP_KERNEL".
Reported-by: Randall S. Becker <randall.becker@nexbridge.ca>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add global counters mechanism to Trace2.
The Trace2 counters mechanism adds the ability to create a set of
global counter variables and an API to increment them efficiently.
Counters can optionally report per-thread usage in addition to the sum
across all threads.
Counter events are emitted to the Trace2 logs when a thread exits and
at process exit.
Counters are an alternative to `data` and `data_json` events.
Counters are useful when you want to measure something across the life
of the process, when you don't want per-measurement events for
performance reasons, when the data does not fit conveniently within a
region, or when your control flow does not easily let you write the
final total. For example, you might use this to report the number of
calls to unzip() or the number of de-delta steps during a checkout.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add stopwatch timer mechanism to Trace2.
Timers are an alternative to Trace2 Regions. Regions are useful for
measuring the time spent in various computation phases, such as the
time to read the index, time to scan for unstaged files, time to scan
for untracked files, and etc.
However, regions are not appropriate in all places. For example,
during a checkout, it would be very inefficient to use regions to
measure the total time spent inflating objects from the ODB from
across the entire lifetime of the process; a per-unzip() region would
flood the output and significantly slow the command; and some form of
post-processing would be requried to compute the time spent in unzip().
Timers can be used to measure a series of timer intervals and emit
a single summary event (at thread and/or process exit).
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Mark all tests that match "*trace2*" as passing when git is compiled
with SANITIZE=leak. They'll now be listed as running under the
"GIT_TEST_PASSING_SANITIZE_LEAK=true" test mode (the "linux-leaks" CI
target).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make use of new sq_append_quote_argv_pretty() to normalize
how we handle leading whitespace in perf format messages.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For an environment variable that is supposed to be set by users, the
GIT_TR2* env vars are just too unclear, inconsistent, and ugly.
Most of the established GIT_* environment variables don't use
abbreviations, and in case of the few that do (GIT_DIR,
GIT_COMMON_DIR, GIT_DIFF_OPTS) it's quite obvious what the
abbreviations (DIR and OPTS) stand for. But what does TR stand for?
Track, traditional, trailer, transaction, transfer, transformation,
transition, translation, transplant, transport, traversal, tree,
trigger, truncate, trust, or ...?!
The trace2 facility, as the '2' suffix in its name suggests, is
supposed to eventually supercede Git's original trace facility. It's
reasonable to expect that the corresponding environment variables
follow suit, and after the original GIT_TRACE variables they are
called GIT_TRACE2; there is no such thing is 'GIT_TR'.
All trace2-specific config variables are, very sensibly, in the
'trace2' section, not in 'tr2'.
OTOH, we don't gain anything at all by omitting the last three
characters of "trace" from the names of these environment variables.
So let's rename all GIT_TR2* environment variables to GIT_TRACE2*,
before they make their way into a stable release.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach git to read the system and global config files for
default Trace2 settings. This allows system-wide Trace2 settings to
be installed and inherited to make it easier to manage a collection of
systems.
The original GIT_TR2* environment variables are loaded afterwards and
can be used to override the system settings.
Only the system and global config files are used. Repo and worktree
local config files are ignored. Likewise, the "-c" command line
arguments are also ignored. These limits are for performance reasons.
(1) For users not using Trace2, there should be minimal overhead to
detect that Trace2 is not enabled. In particular, Trace2 should not
allocate lots of otherwise unused data strucutres.
(2) For accurate performance measurements, Trace2 should be initialized
as early in the git process as possible, and before most of the normal
git process initialization (which involves discovering the .git directory
and reading a hierarchy of config files).
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add elapsed process time to "start" event to measure
the performance of early process startup.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Ævar Arnfjörð Bjarmason
Jeff Hostetler
SZEDER Gábor