From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
linux-kernel@vger.kernel.org, yrl.pp-manager.tt@hitachi.com
Subject: Re: Re: [RFC PATCH 08/11] trace-cmd: Apply the trace-msg protocol for communication between a server and clients
Date: Tue, 27 Aug 2013 19:23:24 +0900 [thread overview]
Message-ID: <521C7E1C.5060502@hitachi.com> (raw)
In-Reply-To: <20130826111105.5d6504e0@gandalf.local.home>
(2013/08/27 0:11), Steven Rostedt wrote:
> On Mon, 26 Aug 2013 10:50:33 +0900
> Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com> wrote:
>
>> <Network>
>> 0. old server and old client
>> Old servers send "tracecmd" as the first message.
>> Old clients compare the first 8byte of the first message with "tracecmd".
>>
>> 1. new server
>> - Send "tracecmd-v2" as the first message.
>> - Check the reply message whether the message is "tracecmd-v2" or cpus
>> value.
>> If "tracecmd-v2", the server uses new protocol and wait for the
>> message MSG_TINIT.
>> If cpus value, the server uses old protocol.
>
> That will kill an old client. Yes it only checks the first 8 bytes, but
> then it gets back a comma separated list of CPUs. As it uses TCP for
> this transaction, the unread "-v2" will end up being read as CPUs by
> the client.
Ah, that's true. This method is inappropriate.
>>
>> 2. new client
>> - Receive the first message.
>> - Check the message whether the message is "tracecmd-v2" or not.
>> If "tracecmd-v2", the client sends "tracecmd-v2" to the server. Then,
>> the client sends the message MSG_TINIT.
>> If "tracecmd", the client sends cpus value as the old protocol.
>>
>
> It will have to be the client that determines if the protocol is v2 or
> not. Basically, after receiving the "tracecmd" the client can send back
> "V2", and then expect the server to reply with "V2" as well. If the
> server does not, then it disconnects from the server and then restarts
> with the old protocol.
OK, let me check that. Even if the old server will receive "V2", the
server will send port numbers instead of "V2" due to the old protocol.
In that time, the new client will disconnect from the old server and
the restarts with the old protocol. Is it OK?
Thanks!
Yoshihiro YUNOMAE
--
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@hitachi.com
next prev parent reply other threads:[~2013-08-27 10:23 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-19 9:46 [RFC PATCH 00/11] trace-cmd: Support the feature recording trace data of guests on the host Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 01/11] [TRIVIAL] trace-cmd: Delete the variable iface in trace-listen Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 02/11] [BUGFIX] trace-cmd: Add waitpid() when recorders are destoried Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 03/11] [BUGFIX]trace-cmd: Quit from splice(read) if there are no data Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 04/11] [CLEANUP] trace-cmd: Split out the communication with listener from setup_network() Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 05/11] [CLEANUP] trace-cmd: Split out the connect waiting loop from do_listen() Yoshihiro YUNOMAE
2013-08-20 17:15 ` Steven Rostedt
2013-08-20 17:18 ` Steven Rostedt
2013-08-19 9:46 ` [RFC PATCH 06/11] [CLEANUP] trace-cmd: Split out the communication with client from process_client() Yoshihiro YUNOMAE
2013-08-20 17:38 ` Steven Rostedt
2013-08-19 9:46 ` [RFC PATCH 07/11] [CLEANUP] trace-cmd: Split out binding a port and fork reader from open_udp() Yoshihiro YUNOMAE
2013-08-20 17:49 ` Steven Rostedt
2013-08-26 1:48 ` Yoshihiro YUNOMAE
2013-08-26 14:37 ` Steven Rostedt
2013-08-27 8:08 ` Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 08/11] trace-cmd: Apply the trace-msg protocol for communication between a server and clients Yoshihiro YUNOMAE
2013-08-20 17:56 ` Steven Rostedt
2013-08-26 1:50 ` Yoshihiro YUNOMAE
2013-08-26 15:11 ` Steven Rostedt
2013-08-27 10:23 ` Yoshihiro YUNOMAE [this message]
2013-08-27 13:05 ` Steven Rostedt
2013-08-28 11:30 ` Yoshihiro YUNOMAE
2013-08-28 14:42 ` Steven Rostedt
2013-08-29 1:57 ` Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 09/11] trace-cmd: Use poll(2) to wait for a message Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 10/11] trace-cmd: Add virt-server mode for a virtualization environment Yoshihiro YUNOMAE
2013-08-19 9:46 ` [RFC PATCH 11/11] trace-cmd: Add --virt option for record mode Yoshihiro YUNOMAE
2013-08-20 16:00 ` [RFC PATCH 00/11] trace-cmd: Support the feature recording trace data of guests on the host Steven Rostedt
2013-08-26 1:46 ` Yoshihiro YUNOMAE
2013-08-26 14:22 ` Steven Rostedt
2013-08-27 8:07 ` Yoshihiro YUNOMAE
2013-08-27 13:00 ` Steven Rostedt
2013-08-28 11:31 ` Yoshihiro YUNOMAE
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