From 3a251bac0d1a05b3dd9df45c45b40e2747829ca3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Mon, 18 Jul 2022 12:31:52 +0200 Subject: [PATCH] trace2: only include "fsync" events if we git_fsync() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix the overly verbose trace2 logging added in 9a4987677d3 (trace2: add stats for fsync operations, 2022-03-30) (first released with v2.36.0). Since that change every single "git" command invocation has included these "data" events, even though we'll only make use of these with core.fsyncMethod=batch, and even then only have non-zero values if we're writing object data to disk. See c0f4752ed2f (core.fsyncmethod: batched disk flushes for loose-objects, 2022-04-04) for that feature. As we're needing to indent the trace2_data_intmax() lines let's introduce helper variables to ensure that our resulting lines (which were already too) don't exceed the recommendations of the CodingGuidelines. Doing that requires either wrapping them twice, or introducing short throwaway variable names, let's do the latter. The result was that e.g. "git version" would previously emit a total of 6 trace2 events with the GIT_TRACE2_EVENT target (version, start, cmd_ancestry, cmd_name, exit, atexit), but afterwards would emit 8. We'd emit 2 "data" events before the "exit" event. The reason we didn't catch this was that the trace2 unit tests added in a15860dca3f (trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh, 2019-02-22) would omit any "data" events that weren't the ones it cared about. Before this change to the C code 6/7 of our "t/t0212-trace2-event.sh" tests would fail if this change was applied to "t/t0212/parse_events.perl". Let's make the trace2 testing more strict, and further append any new events types we don't know about in "t/t0212/parse_events.perl". Since we only invoke the "test-tool trace2" there's no guarantee that we'll catch other overly verbose events in the future, but we'll at least notice if we start emitting new events that are issues every time we log anything with trace2's JSON target. We exclude the "data_json" event type, we'd otherwise would fail on both "win test" and "win+VS test" CI due to the logging added in 353d3d77f4f (trace2: collect Windows-specific process information, 2019-02-22). It looks like that logging should really be using trace2_cmd_ancestry() instead, which was introduced later in 2f732bf15e6 (tr2: log parent process name, 2021-07-21), but let's leave it for now. The fix-up to aaf81223f48 (unpack-objects: use stream_loose_object() to unpack large objects, 2022-06-11) is needed because we're changing the behavior of these events as discussed above. Since we'd always emit a "hardware-flush" event the test added in aaf81223f48 wasn't testing anything except that this trace2 data was unconditionally logged. Even if "core.fsyncMethod" wasn't set to "batch" we'd pass the test. Now we'll check the expected number of "writeout" v.s. "flush" calls under "core.fsyncMethod=batch", but note that this doesn't actually test if we carried out the sync using that method, on a platform where we'd have to fall back to fsync() each of those "writeout" would really be a "flush" (i.e. a full fsync()). But in this case what we're testing is that the logic in "unpack-objects" behaves as expected, not the OS-specific question of whether we actually were able to use the "bulk" method. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- t/t0212/parse_events.perl | 19 +++++++++++++------ t/t5351-unpack-large-objects.sh | 22 +++++++++++++++++++++- wrapper.c | 10 ++++++++-- 3 files changed, 42 insertions(+), 9 deletions(-) diff --git a/t/t0212/parse_events.perl b/t/t0212/parse_events.perl index b6408560c0..30a9f51e9f 100644 --- a/t/t0212/parse_events.perl +++ b/t/t0212/parse_events.perl @@ -216,12 +216,19 @@ while (<>) { elsif ($event eq 'data') { my $cat = $line->{'category'}; - if ($cat eq 'test_category') { - - my $key = $line->{'key'}; - my $value = $line->{'value'}; - $processes->{$sid}->{'data'}->{$cat}->{$key} = $value; - } + my $key = $line->{'key'}; + my $value = $line->{'value'}; + $processes->{$sid}->{'data'}->{$cat}->{$key} = $value; + } + + elsif ($event eq 'data_json') { + # NEEDSWORK: Ignore due to + # compat/win32/trace2_win32_process_info.c, which should log a + # "cmd_ancestry" event instead. + } + + else { + push @{$processes->{$sid}->{$event}} => $line->{value}; } # This trace2 target does not emit 'printf' events. diff --git a/t/t5351-unpack-large-objects.sh b/t/t5351-unpack-large-objects.sh index 8ce8aa3b14..f785cb0617 100755 --- a/t/t5351-unpack-large-objects.sh +++ b/t/t5351-unpack-large-objects.sh @@ -48,13 +48,33 @@ test_expect_success 'unpack big object in stream' ' test_dir_is_empty dest.git/objects/pack ' +check_fsync_events () { + local trace="$1" && + shift && + + cat >expect && + sed -n \ + -e '/^{"event":"data",.*"category":"fsync",/ { + s/.*"category":"fsync",//; + s/}$//; + p; + }' \ + <"$trace" >actual && + test_cmp expect actual +} + BATCH_CONFIGURATION='-c core.fsync=loose-object -c core.fsyncmethod=batch' test_expect_success 'unpack big object in stream (core.fsyncmethod=batch)' ' prepare_dest 1m && GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \ + GIT_TEST_FSYNC=true \ git -C dest.git $BATCH_CONFIGURATION unpack-objects current && cmp obj-list current diff --git a/wrapper.c b/wrapper.c index 1c3c970080..cfe79bd081 100644 --- a/wrapper.c +++ b/wrapper.c @@ -616,10 +616,16 @@ int git_fsync(int fd, enum fsync_action action) } } +static void log_trace_fsync_if(const char *key, intmax_t value) +{ + if (value) + trace2_data_intmax("fsync", the_repository, key, value); +} + void trace_git_fsync_stats(void) { - trace2_data_intmax("fsync", the_repository, "fsync/writeout-only", count_fsync_writeout_only); - trace2_data_intmax("fsync", the_repository, "fsync/hardware-flush", count_fsync_hardware_flush); + log_trace_fsync_if("fsync/writeout-only", count_fsync_writeout_only); + log_trace_fsync_if("fsync/hardware-flush", count_fsync_hardware_flush); } static int warn_if_unremovable(const char *op, const char *file, int rc)