Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/doc/dev/messenger.rst b/doc/dev/messenger.rst
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+============================
+ Messenger notes
+============================
+
+Messenger is the Ceph network layer implementation. Currently Ceph supports
+one messenger type: "async".
+
+ceph_perf_msgr
+==============
+
+ceph_perf_msgr is used to do benchmark for messenger module only and can help
+to find the bottleneck or time consuming within messenger moduleIt just like
+"iperf", we need to start server-side program firstly:
+
+# ./ceph_perf_msgr_server 172.16.30.181:10001 1 0
+
+The first argument is ip:port pair which is telling the destination address the
+client need to specified. The second argument configures the server threads. The
+third argument tells the "think time"(us) when dispatching messages. After Giant,
+CEPH_OSD_OP message which is the actual client read/write io request is fast
+dispatched without queueing to Dispatcher, in order to achieve better performance.
+So CEPH_OSD_OP message will be processed inline, "think time" is used by mock
+this "inline process" process.
+
+# ./ceph_perf_msgr_client 172.16.30.181:10001 1 32 10000 10 4096 
+
+The first argument is specified the server ip:port, and the second argument is
+used to specify client threads. The third argument specify the concurrency(the
+max inflight messages for each client thread), the fourth argument specify the
+io numbers will be issued to server per client thread. The fifth argument is
+used to indicate the "think time" for client thread when receiving messages,
+this is also used to mock the client fast dispatch process. The last argument
+specify the message data length to issue.