X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=blktrace.c;h=d0d271f9add5106b4481321058787f1ba1aa82a4;hb=d025d6c67760a52e34e6c7352f33ad5dbbb4f6f4;hp=3a25338cc9ad271a82fa30dbae1aa0ccb0e21cba;hpb=d7a1f72671eb67a7d0cd261ea4520b9551c51f5f;p=blktrace.git

diff --git a/blktrace.c b/blktrace.c
index 3a25338..d0d271f 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -112,6 +112,7 @@ struct devpath {
 	struct cl_host *ch;
 	u32 cl_id;
 	time_t cl_connect_time;
+	int setup_done;	/* ioctl BLKTRACESETUP done */
 	struct io_info *ios;
 };
 
@@ -1066,9 +1067,10 @@ static void close_client_connections(void)
 	}
 }
 
-static void setup_buts(void)
+static int setup_buts(void)
 {
 	struct list_head *p;
+	int ret = 0;
 
 	__list_for_each(p, &devpaths) {
 		struct blk_user_trace_setup buts;
@@ -1082,14 +1084,19 @@ static void setup_buts(void)
 		if (ioctl(dpp->fd, BLKTRACESETUP, &buts) >= 0) {
 			dpp->ncpus = max_cpus;
 			dpp->buts_name = strdup(buts.name);
+			dpp->setup_done = 1;
 			if (dpp->stats)
 				free(dpp->stats);
 			dpp->stats = calloc(dpp->ncpus, sizeof(*dpp->stats));
 			memset(dpp->stats, 0, dpp->ncpus * sizeof(*dpp->stats));
-		} else
+		} else {
 			fprintf(stderr, "BLKTRACESETUP(2) %s failed: %d/%s\n",
 				dpp->path, errno, strerror(errno));
+			ret++;
+		}
 	}
+
+	return ret;
 }
 
 static void start_buts(void)
@@ -1280,7 +1287,8 @@ static void rel_devpaths(void)
 		struct devpath *dpp = list_entry(p, struct devpath, head);
 
 		list_del(&dpp->head);
-		__stop_trace(dpp->fd);
+		if (dpp->setup_done)
+			__stop_trace(dpp->fd);
 		close(dpp->fd);
 
 		if (dpp->heads)
@@ -1893,6 +1901,26 @@ static int start_tracer(int cpu)
 	return 0;
 }
 
+static int create_output_files(int cpu)
+{
+	char fname[MAXPATHLEN + 64];
+	struct list_head *p;
+	FILE *f;
+
+	__list_for_each(p, &devpaths) {
+		struct devpath *dpp = list_entry(p, struct devpath, head);
+
+		if (fill_ofname(fname, sizeof(fname), NULL, dpp->buts_name,
+				cpu))
+			return 1;
+		f = my_fopen(fname, "w+");
+		if (!f)
+			return 1;
+		fclose(f);
+	}
+	return 0;
+}
+
 static void start_tracers(void)
 {
 	int cpu, started = 0;
@@ -1900,8 +1928,16 @@ static void start_tracers(void)
 	size_t alloc_size = CPU_ALLOC_SIZE(max_cpus);
 
 	for (cpu = 0; cpu < max_cpus; cpu++) {
-		if (!CPU_ISSET_S(cpu, alloc_size, online_cpus))
+		if (!CPU_ISSET_S(cpu, alloc_size, online_cpus)) {
+			/*
+			 * Create fake empty output files so that other tools
+			 * like blkparse don't have to bother with sparse CPU
+			 * number space.
+			 */
+			if (create_output_files(cpu))
+				break;
 			continue;
+		}
 		if (start_tracer(cpu))
 			break;
 		started++;
@@ -2648,7 +2684,8 @@ static int run_tracers(void)
 	if (net_mode == Net_client)
 		printf("blktrace: connecting to %s\n", hostname);
 
-	setup_buts();
+	if (setup_buts())
+		return 1;
 
 	if (use_tracer_devpaths()) {
 		if (setup_tracer_devpaths())