nbd: trace long NBD operations

At the moment there are 2 sources of lengthy operations if configured:
* open connection, which could retry inside and
* reconnect of already opened connection
These operations could be quite lengthy and cumbersome to catch thus
it would be quite natural to add trace points for them.

This patch is based on the original downstream work made by Vladimir.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Eric Blake <eblake@redhat.com>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Hanna Reitz <hreitz@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

diff --git a/block/nbd.c b/block/nbd.c
index 7f5f50ec46aa7e4247466995f61b1f0c7abc27f7..5849d312cc681008eb859b3104877835c38cae74 100644 (file)
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -371,6 +371,7 @@ static bool nbd_client_connecting(BDRVNBDState *s)
 /* Called with s->requests_lock taken.  */
 static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
 {
+    int ret;
     bool blocking = s->state == NBD_CLIENT_CONNECTING_WAIT;
 
     /*
@@ -380,6 +381,8 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
     assert(nbd_client_connecting(s));
     assert(s->in_flight == 1);
 
+    trace_nbd_reconnect_attempt(s->bs->in_flight);
+
     if (blocking && !s->reconnect_delay_timer) {
         /*
          * It's the first reconnect attempt after switching to
@@ -401,7 +404,8 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
     }
 
     qemu_mutex_unlock(&s->requests_lock);
-    nbd_co_do_establish_connection(s->bs, blocking, NULL);
+    ret = nbd_co_do_establish_connection(s->bs, blocking, NULL);
+    trace_nbd_reconnect_attempt_result(ret, s->bs->in_flight);
     qemu_mutex_lock(&s->requests_lock);
 
     /*

diff --git a/block/trace-events b/block/trace-events
index 549090d453e7a1c262bfd3f86d748c63bc531504..48dbf10c66fef19096bdb5650f8b0b3f18e1d195 100644 (file)
--- a/block/trace-events
+++ b/block/trace-events
@@ -172,6 +172,8 @@ nbd_read_reply_entry_fail(int ret, const char *err) "ret = %d, err: %s"
 nbd_co_request_fail(uint64_t from, uint32_t len, uint64_t handle, uint16_t flags, uint16_t type, const char *name, int ret, const char *err) "Request failed { .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64 ", .flags = 0x%" PRIx16 ", .type = %" PRIu16 " (%s) } ret = %d, err: %s"
 nbd_client_handshake(const char *export_name) "export '%s'"
 nbd_client_handshake_success(const char *export_name) "export '%s'"
+nbd_reconnect_attempt(unsigned in_flight) "in_flight %u"
+nbd_reconnect_attempt_result(int ret, unsigned in_flight) "ret %d in_flight %u"
 
 # ssh.c
 ssh_restart_coroutine(void *co) "co=%p"

diff --git a/nbd/client-connection.c b/nbd/client-connection.c
index 2a632931c393d07fb4dd8c8079ccc4614b313f06..0c5f917efac0b86e56e8dd5dfa4c9b4ee6bbb3b4 100644 (file)
--- a/nbd/client-connection.c
+++ b/nbd/client-connection.c
@@ -23,6 +23,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "trace.h"
 
 #include "block/nbd.h"
 
@@ -210,6 +211,7 @@ static void *connect_thread_func(void *opaque)
             object_unref(OBJECT(conn->sioc));
             conn->sioc = NULL;
             if (conn->do_retry && !conn->detached) {
+                trace_nbd_connect_thread_sleep(timeout);
                 qemu_mutex_unlock(&conn->mutex);
 
                 sleep(timeout);

diff --git a/nbd/trace-events b/nbd/trace-events
index c4919a2dd581b642acb0b1e7cd1d4105ca4d0477..b7032ca2778a2cd85bfa614ae41f14ad530872af 100644 (file)
--- a/nbd/trace-events
+++ b/nbd/trace-events
@@ -73,3 +73,6 @@ nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char *n
 nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len) "Payload received: handle = %" PRIu64 ", len = %" PRIu32
 nbd_co_receive_align_compliance(const char *op, uint64_t from, uint32_t len, uint32_t align) "client sent non-compliant unaligned %s request: from=0x%" PRIx64 ", len=0x%" PRIx32 ", align=0x%" PRIx32
 nbd_trip(void) "Reading request"
+
+# client-connection.c
+nbd_connect_thread_sleep(uint64_t timeout) "timeout %" PRIu64