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api: mark api_trace_command_fn thread-safe

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Binary API trace replay with multiple worker threads depends in many
cases on worker thread graph replica maintenance. If we (implicitly)
assert a worker thread barrier at the debug CLI level, all graph
replica changes are deferred until the replay operation completes. If
an interface is deleted, the wheels may fall off.

Type: fix
Ticket: VPP-1824

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I9b07d43f8501caa5519e5ff9ae4c19dc2661cc84
This commit is contained in:
Dave Barach
2020-01-23 08:44:40 -05:00
committed by Dave Barach
parent 418b225931
commit c385a95e8e
1 changed files with 20 additions and 1 deletions
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21
src/vlibmemory/vlib_api_cli.c
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@ -662,6 +662,16 @@ vl_msg_api_process_file (vlib_main_t * vm, u8 * filename,
am->replay_in_progress = 0; am->replay_in_progress = 0;
} }
/** api_trace_command_fn - control the binary API trace / replay feature
Note: this command MUST be marked thread-safe. Replay with
multiple worker threads depends in many cases on worker thread
graph replica maintenance. If we (implicitly) assert a worker
thread barrier at the debug CLI level, all graph replica changes
are deferred until the replay operation completes. If an interface
is deleted, the wheels fall off.
*/
static clib_error_t * static clib_error_t *
api_trace_command_fn (vlib_main_t * vm, api_trace_command_fn (vlib_main_t * vm,
unformat_input_t * input, vlib_cli_command_t * cmd) unformat_input_t * input, vlib_cli_command_t * cmd)
@ -682,12 +692,16 @@ api_trace_command_fn (vlib_main_t * vm,
{ {
if (unformat (input, "nitems %d", &nitems)) if (unformat (input, "nitems %d", &nitems))
; ;
vlib_worker_thread_barrier_sync (vm);
vl_msg_api_trace_configure (am, which, nitems); vl_msg_api_trace_configure (am, which, nitems);
vl_msg_api_trace_onoff (am, which, 1 /* on */ ); vl_msg_api_trace_onoff (am, which, 1 /* on */ );
vlib_worker_thread_barrier_release (vm);
} }
else if (unformat (input, "off")) else if (unformat (input, "off"))
{ {
vlib_worker_thread_barrier_sync (vm);
vl_msg_api_trace_onoff (am, which, 0); vl_msg_api_trace_onoff (am, which, 0);
vlib_worker_thread_barrier_release (vm);
} }
else if (unformat (input, "save %s", &filename)) else if (unformat (input, "save %s", &filename))
{ {
@ -709,7 +723,9 @@ api_trace_command_fn (vlib_main_t * vm,
vlib_cli_output (vm, "Couldn't create %s\n", chroot_filename); vlib_cli_output (vm, "Couldn't create %s\n", chroot_filename);
goto out; goto out;
} }
vlib_worker_thread_barrier_sync (vm);
rv = vl_msg_api_trace_save (am, which, fp); rv = vl_msg_api_trace_save (am, which, fp);
vlib_worker_thread_barrier_release (vm);
fclose (fp); fclose (fp);
if (rv == -1) if (rv == -1)
vlib_cli_output (vm, "API Trace data not present\n"); vlib_cli_output (vm, "API Trace data not present\n");
@ -766,8 +782,10 @@ api_trace_command_fn (vlib_main_t * vm,
} }
else if (unformat (input, "free")) else if (unformat (input, "free"))
{ {
vlib_worker_thread_barrier_sync (vm);
vl_msg_api_trace_onoff (am, which, 0); vl_msg_api_trace_onoff (am, which, 0);
vl_msg_api_trace_free (am, which); vl_msg_api_trace_free (am, which);
vlib_worker_thread_barrier_release (vm);
} }
else if (unformat (input, "post-mortem-on")) else if (unformat (input, "post-mortem-on"))
vl_msg_api_post_mortem_dump_enable_disable (1 /* enable */ ); vl_msg_api_post_mortem_dump_enable_disable (1 /* enable */ );
@ -792,8 +810,9 @@ VLIB_CLI_COMMAND (api_trace_command, static) =
{ {
.path = "api trace", .path = "api trace",
.short_help = "api trace [on|off][first <n>][last <n>][status][free]" .short_help = "api trace [on|off][first <n>][last <n>][status][free]"
"[post-mortem-on][dump|custom-dump|save|replay <file>]", "[post-mortem-on][dump|custom-dump|save|replay <file>]",
.function = api_trace_command_fn, .function = api_trace_command_fn,
.is_mp_safe = 1,
}; };
/* *INDENT-ON* */ /* *INDENT-ON* */