blktrace: probe IO depth

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/blktrace.c b/blktrace.c
index 4b5567effe6ab2624079df36284df4ad524d0f19..649cb83e702654c5d2f9267b3b992469b718a183 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -373,6 +373,7 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
        struct fifo *fifo;
        int fd, i, old_state;
        struct fio_file *f;
+       int this_depth, depth;
 
        fd = open(filename, O_RDONLY);
        if (fd < 0) {
@@ -391,6 +392,7 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
        ios[0] = ios[1] = 0;
        rw_bs[0] = rw_bs[1] = 0;
        skipped_writes = 0;
+       this_depth = depth = 0;
        do {
                int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));
 
@@ -425,6 +427,12 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
                        goto err;
                }
                if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
+                       if ((t.action & 0xffff) == __BLK_TA_QUEUE)
+                               this_depth++;
+                       else if ((t.action & 0xffff) == __BLK_TA_COMPLETE) {
+                               depth = max(depth, this_depth);
+                               this_depth = 0;
+                       }
                        if (!ttime) {
                                ttime = t.time;
                                cpu = t.cpu;
@@ -469,6 +477,13 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
                return 1;
        }
 
+       /*
+        * For stacked devices, we don't always get a COMPLETE event so
+        * the depth grows to insane values. Limit it to something sane(r).
+        */
+       if (!depth || depth > 1024)
+               depth = 1024;
+
        if (skipped_writes)
                log_err("fio: %s skips replay of %lu writes due to read-only\n",
                                                td->o.name, skipped_writes);
@@ -494,6 +509,13 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
         */
        td->o.odirect = 1;
 
+       /*
+        * we don't know if this option was set or not. it defaults to 1,
+        * so we'll just guess that we should override it if it's still 1
+        */
+       if (td->o.iodepth != 1)
+               td->o.iodepth = depth;
+
        return 0;
 err:
        close(fd);