mirror of
https://github.com/git/git.git
synced 2024-05-12 02:26:28 +02:00
ee4512ed48
Create a new unified tracing facility for git. The eventual intent is to replace the current trace_printf* and trace_performance* routines with a unified set of git_trace2* routines. In addition to the usual printf-style API, trace2 provides higer-level event verbs with fixed-fields allowing structured data to be written. This makes post-processing and analysis easier for external tools. Trace2 defines 3 output targets. These are set using the environment variables "GIT_TR2", "GIT_TR2_PERF", and "GIT_TR2_EVENT". These may be set to "1" or to an absolute pathname (just like the current GIT_TRACE). * GIT_TR2 is intended to be a replacement for GIT_TRACE and logs command summary data. * GIT_TR2_PERF is intended as a replacement for GIT_TRACE_PERFORMANCE. It extends the output with columns for the command process, thread, repo, absolute and relative elapsed times. It reports events for child process start/stop, thread start/stop, and per-thread function nesting. * GIT_TR2_EVENT is a new structured format. It writes event data as a series of JSON records. Calls to trace2 functions log to any of the 3 output targets enabled without the need to call different trace_printf* or trace_performance* routines. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
#include "cache.h"
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#include "trace2/tr2_sid.h"
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#define TR2_ENVVAR_PARENT_SID "GIT_TR2_PARENT_SID"
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static struct strbuf tr2sid_buf = STRBUF_INIT;
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static int tr2sid_nr_git_parents;
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/*
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* Compute a "unique" session id (SID) for the current process. This allows
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* all events from this process to have a single label (much like a PID).
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*
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* Export this into our environment so that all child processes inherit it.
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*
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* If we were started by another git instance, use our parent's SID as a
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* prefix. (This lets us track parent/child relationships even if there
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* is an intermediate shell process.)
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*
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* Additionally, count the number of nested git processes.
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*/
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static void tr2_sid_compute(void)
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{
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uint64_t us_now;
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const char *parent_sid;
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if (tr2sid_buf.len)
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return;
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parent_sid = getenv(TR2_ENVVAR_PARENT_SID);
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if (parent_sid && *parent_sid) {
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const char *p;
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for (p = parent_sid; *p; p++)
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if (*p == '/')
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tr2sid_nr_git_parents++;
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strbuf_addstr(&tr2sid_buf, parent_sid);
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strbuf_addch(&tr2sid_buf, '/');
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tr2sid_nr_git_parents++;
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}
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us_now = getnanotime() / 1000;
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strbuf_addf(&tr2sid_buf, "%" PRIuMAX "-%" PRIdMAX, (uintmax_t)us_now,
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(intmax_t)getpid());
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setenv(TR2_ENVVAR_PARENT_SID, tr2sid_buf.buf, 1);
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}
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const char *tr2_sid_get(void)
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{
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if (!tr2sid_buf.len)
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tr2_sid_compute();
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return tr2sid_buf.buf;
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}
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int tr2_sid_depth(void)
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{
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if (!tr2sid_buf.len)
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tr2_sid_compute();
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return tr2sid_nr_git_parents;
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}
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void tr2_sid_release(void)
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{
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strbuf_release(&tr2sid_buf);
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}
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