From: Daniel Stodden <daniel.stodden@citrix.com>
Date: Fri, 10 Apr 2009 03:49:40 +0000 (-0700)
Subject: CA-27472: Count/log incoming/outgoing VBD kicks in tapdisk.
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=2e160f2e560bc5ac06d61252e1c9dfab6abc47c3;p=people%2Fdstodden%2Fblktap.git

CA-27472: Count/log incoming/outgoing VBD kicks in tapdisk.

The notification count helps debugging some interesting VBD
problems. One is that that dom0 plugs have a problem with batching
requests issued through the frontend device (xvd). Looks like there is
no batching at all.
---

diff --git a/drivers/tapdisk-vbd.c b/drivers/tapdisk-vbd.c
index d0b548b..01e547a 100644
--- a/drivers/tapdisk-vbd.c
+++ b/drivers/tapdisk-vbd.c
@@ -859,10 +859,11 @@ tapdisk_vbd_shutdown(td_vbd_t *vbd)
 		vbd->name, vbd->state, new, pending, failed, completed);
 	DPRINTF("last activity: %010ld.%06ld, errors: 0x%04"PRIx64", "
 		"retries: 0x%04"PRIx64", received: 0x%08"PRIx64", "
-		"returned: 0x%08"PRIx64", kicked: 0x%08"PRIx64"\n",
+		"returned: 0x%08"PRIx64", kicked: 0x%08"PRIx64", "
+		"kicks in: 0x%08"PRIx64", out: 0x%08"PRIu64"\n",
 		vbd->ts.tv_sec, vbd->ts.tv_usec,
 		vbd->errors, vbd->retries, vbd->received, vbd->returned,
-		vbd->kicked);
+		vbd->kicked, vbd->kicks_in, vbd->kicks_out);
 	DPRINTF("failure cnt: %d ttl min: %.3f max: %.3f avg: %.3f stdev: %.3f\n",
 		vbd->failure_ttl.k,
 		TD_STATS_MIN(&vbd->failure_ttl), TD_STATS_MAX(&vbd->failure_ttl),
@@ -923,10 +924,12 @@ tapdisk_vbd_debug(td_vbd_t *vbd)
 	DBG(TLOG_WARN, "%s: state: 0x%08x, new: 0x%02x, pending: 0x%02x, "
 	    "failed: 0x%02x, completed: 0x%02x, last activity: %010ld.%06ld, "
 	    "errors: 0x%04llx, retries: 0x%04llx, received: 0x%08llx, "
-	    "returned: 0x%08llx, kicked: 0x%08llx\n",
+	    "returned: 0x%08llx, kicked: 0x%08llx, "
+	    "kicks in: 0x%08"PRIx64", out: 0x%08"PRIx64"\n",
 	    vbd->name, vbd->state, new, pending, failed, completed,
 	    vbd->ts.tv_sec, vbd->ts.tv_usec, vbd->errors, vbd->retries,
-	    vbd->received, vbd->returned, vbd->kicked);
+	    vbd->received, vbd->returned, vbd->kicked,
+	    vbd->kicks_in, vbd->kicks_out);
 
 	tapdisk_vbd_for_each_image(vbd, image, tmp)
 		td_debug(image);
@@ -1141,6 +1144,7 @@ tapdisk_vbd_kick(td_vbd_t *vbd)
 	if (!n)
 		return 0;
 
+	vbd->kicks_out++;
 	vbd->kicked += n;
 	RING_PUSH_RESPONSES(&ring->fe_ring);
 	ioctl(ring->fd, BLKTAP_IOCTL_KICK_FE, 0);
@@ -1803,6 +1807,7 @@ tapdisk_vbd_ring_event(event_id_t id, char mode, void *private)
 
 	vbd = (td_vbd_t *)private;
 
+	vbd->kicks_in++;
 	tapdisk_vbd_pull_ring_requests(vbd);
 	tapdisk_vbd_issue_requests(vbd);
 
diff --git a/drivers/tapdisk-vbd.h b/drivers/tapdisk-vbd.h
index ca67f29..28ba1ac 100644
--- a/drivers/tapdisk-vbd.h
+++ b/drivers/tapdisk-vbd.h
@@ -122,6 +122,9 @@ struct td_vbd_handle {
 	uint64_t                    retries;
 	uint64_t                    errors;
 
+	uint64_t                    kicks_in;
+	uint64_t                    kicks_out;
+
 	struct dispersion           failure_ttl;
 };