Commit d5901de3 authored by Jim Harris's avatar Jim Harris
Browse files

spdk_trace: default on Linux to newest trace file in /dev/shm 



It is kind of a pain to have to *always* have to specify the filename
or app parameters to spdk_trace, especially when you have the app currently
running or the app just exited.

So use ntfw() to walk the files in /dev/shm when -f and -s are not specified,
and use the newest file (assuming one is found).

A few caveats:
1) This only works on Linux, mainly because FreeBSD does not have a /dev/shm
   mount for shm files.
2) Search /dev/shm is not foolproof, since we don't know for sure whether a
   file there is an SPDK trace file. But looking for the "_trace." substring
   should be enough. It should guard against trying to use other non-trace
   files.

Signed-off-by: default avatarJim Harris <jim.harris@samsung.com>
Change-Id: If130e6f5918a228b6f9d4576e16d37e05bfc4995
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/22104


Reviewed-by: default avatarKonrad Sztyber <konrad.sztyber@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: default avatarBen Walker <ben@nvidia.com>
parent a5156f64

CHANGELOG.md

+6 −0
Original line number Diff line number Diff line
@@ -36,6 +36,12 @@ Added support for namespace masking using new C APIs `spdk_nvmf_ns_add_host` and 
Users must pass new `--no-auto-visible` parameter to `nvmf_subsystem_add_ns` RPC to allow

namespace masking to be controlled by these new RPCs.



### spdk_trace



`spdk_trace` has learned how to use the most recent trace file in /dev/shm when

the user has specified neither `-f` nor `-s` options. This is only available on

Linux since FreeBSD does not mount have a /dev/shm mount.



## v24.01



### accel

app/trace/trace.cpp

+32 −0
Original line number Diff line number Diff line
@@ -340,9 +340,29 @@ usage(void) 
	fprintf(stderr, "                       -i or -p must be specified)\n");

	fprintf(stderr, "                 '-f' to specify a tracepoint file name\n");

	fprintf(stderr, "                      (-s and -f are mutually exclusive)\n");

#if defined(__linux__)

	fprintf(stderr, "                 Without -s or -f, %s will look for\n", g_exe_name);

	fprintf(stderr, "                      newest trace file in /dev/shm\n");

#endif

	fprintf(stderr, "                 '-j' to use JSON to format the output\n");

}



#if defined(__linux__)

static time_t g_mtime = 0;

static char g_newest_file[PATH_MAX] = {};



static int

get_newest(const char *path, const struct stat *sb, int tflag, struct FTW *ftw)

{

	if (tflag == FTW_F && sb->st_mtime > g_mtime &&

	    strstr(path, SPDK_TRACE_SHM_NAME_BASE) != NULL) {

		g_mtime = sb->st_mtime;

		strncpy(g_newest_file, path, PATH_MAX - 1);

	}

	return 0;

}

#endif



int

main(int argc, char **argv)

{
@@ -400,9 +420,21 @@ main(int argc, char **argv) 
	}



	if (file_name == NULL && app_name == NULL) {

#if defined(__linux__)

		nftw("/dev/shm", get_newest, 1, 0);

		if (strlen(g_newest_file) > 0) {

			file_name = g_newest_file;

			printf("Using newest trace file found: %s\n", file_name);

		} else {

			fprintf(stderr, "No shm file found and -f not specified\n");

			usage();

			exit(1);

		}

#else

		fprintf(stderr, "One of -f and -s must be specified\n");

		usage();

		exit(1);

#endif

	}



	if (json) {

include/spdk/stdinc.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ extern "C" { 
#include <dirent.h>

#include <fcntl.h>

#include <fnmatch.h>

#include <ftw.h>

#include <glob.h>

#include <ifaddrs.h>

#include <libgen.h>

lib/event/app.c

+2 −0
Original line number Diff line number Diff line
@@ -524,6 +524,8 @@ app_setup_trace(struct spdk_app_opts *opts) 
			       opts->shm_id >= 0 ? "-i" : "-p",

			       opts->shm_id >= 0 ? opts->shm_id : getpid());

#if defined(__linux__)

		SPDK_NOTICELOG("'spdk_trace' without parameters will also work if this is the only\n");

		SPDK_NOTICELOG("SPDK application currently running.\n");

		SPDK_NOTICELOG("Or copy /dev/shm%s for offline analysis/debug.\n", shm_name);

#endif

	}