blkiomon: drv_data traces pass-through

This patch adds pass-through support for device driver specific traces
to blkiomon. This way we can aggregate block I/O statistics and device
driver specific statistics at the same time.

Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/blkiomon.c b/blkiomon.c
index 3ac43606ec3895376c8663d46e69de01e667412e..435d5d30b760d009e85d1164ba67e0d67237b6b4 100644 (file)
--- a/blkiomon.c
+++ b/blkiomon.c
@@ -88,7 +88,7 @@ static struct rb_root dstat_tree[2] = { RB_ROOT, RB_ROOT };
 static struct dstat *dstat_list[2] = {};
 static int dstat_curr = 0;
 
-static struct output human, binary, debug;
+static struct output drvdata, human, binary, debug;
 
 static char *msg_q_name = NULL;
 static int msg_q_id = -1, msg_q = -1;
@@ -427,6 +427,26 @@ static struct trace *blkiomon_do_trace(struct trace *t)
        return t_old;
 }
 
+static int blkiomon_dump_drvdata(struct blk_io_trace *bit, void *pdu_buf)
+{
+       if (!drvdata.fn)
+               return 0;
+
+       if (fwrite(bit, sizeof(*bit), 1, drvdata.fp) != 1)
+               goto failed;
+       if (fwrite(pdu_buf, bit->pdu_len, 1, drvdata.fp) != 1)
+               goto failed;
+       if (drvdata.pipe && fflush(drvdata.fp))
+               goto failed;
+       return 0;
+
+failed:
+       fprintf(stderr, "blkiomon: could not write to %s\n", drvdata.fn);
+       fclose(drvdata.fp);
+       drvdata.fn = NULL;
+       return 1;
+}
+
 static int blkiomon_do_fifo(void)
 {
        struct trace *t;
@@ -473,6 +493,14 @@ static int blkiomon_do_fifo(void)
 
                t->sequence = sequence++;
 
+               /* forward low-level device driver trace to other tool */
+               if (bit->action & BLK_TC_ACT(BLK_TC_DRV_DATA)) {
+                       driverdata++;
+                       if (blkiomon_dump_drvdata(bit, pdu_buf))
+                               break;
+                       continue;
+               }
+
                if (!(bit->action & BLK_TC_ACT(BLK_TC_ISSUE | BLK_TC_COMPLETE)))
                        continue;
 
@@ -557,7 +585,7 @@ static void blkiomon_debug(void)
                leftover, match, mismatch, driverdata, sequence);
 }
 
-#define S_OPTS "b:D:h:I:Q:q:m:V"
+#define S_OPTS "b:d:D:h:I:Q:q:m:V"
 
 static char usage_str[] = "\n\nblkiomon " \
        "-I <interval>       | --interval=<interval>\n" \
@@ -571,6 +599,7 @@ static char usage_str[] = "\n\nblkiomon " \
        "\t-I   Sample interval.\n" \
        "\t-h   Human-readable output file.\n" \
        "\t-b   Binary output file.\n" \
+       "\t-d   Output file for data emitted by low level device driver.\n" \
        "\t-D   Output file for debugging data.\n" \
        "\t-Qqm Output to message queue using given ID for messages.\n" \
        "\t-V   Print program version.\n\n";
@@ -588,6 +617,12 @@ static struct option l_opts[] = {
                .flag = NULL,
                .val = 'b'
        },
+       {
+               .name = "dump-lldd",
+               .has_arg = required_argument,
+               .flag = NULL,
+               .val = 'd'
+       },
        {
                .name = "debug",
                .has_arg = required_argument,
@@ -652,6 +687,9 @@ int main(int argc, char *argv[])
                case 'b':
                        binary.fn = optarg;
                        break;
+               case 'd':
+                       drvdata.fn = optarg;
+                       break;
                case 'D':
                        debug.fn = optarg;
                        break;
@@ -691,6 +729,8 @@ int main(int argc, char *argv[])
                return 1;
        if (blkiomon_open_output(&binary))
                return 1;
+       if (blkiomon_open_output(&drvdata))
+               return 1;
        if (blkiomon_open_output(&debug))
                return 1;
        if (blkiomon_open_msg_q())