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Subject: Re: [PATCH v3 0/6] Several changes for the UPIU trace
From:   Bean Huo <huobean@gmail.com>
To:     Avri Altman <Avri.Altman@wdc.com>,
        "alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
        "asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "stanley.chu@mediatek.com" <stanley.chu@mediatek.com>,
        "beanhuo@micron.com" <beanhuo@micron.com>,
        "bvanassche@acm.org" <bvanassche@acm.org>,
        "tomas.winkler@intel.com" <tomas.winkler@intel.com>,
        "cang@codeaurora.org" <cang@codeaurora.org>,
        "rostedt@goodmis.org" <rostedt@goodmis.org>,
        "joe@perches.com" <joe@perches.com>
Cc:     "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Date:   Mon, 14 Dec 2020 23:37:30 +0100
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On Mon, 2020-12-14 at 22:13 +0000, Avri Altman wrote:
> Bean Hi,
> I support this series.
> I think it is a good idea to print the response on complete,
> But you need to change the prefix strings, otherwise you are breaking
> the current parsers.
> 
> Say that you have a trace log, generated sometime during 2020 using
> the current upiu trace.
> It would look something like:
> "send" <request upiu>
> "complete" <request upiu>
> 
> And another log generated sometime during 2021 after your change is
> merged:
> "send" <request upiu>
> "complete" < ****response upiu ****>
> 
> The current parser won't be able to differentiate between those logs.
> Just change the prefix strings to be "send_req" and "complete_rsp",
> or something,
> so the parsing tools that support the new format will be able to
> differentiate it from the old one.

Avri,
I still don't understand, this change doesn't break you current parser.
if you still trace "send", "complete", "CDB", "query_send/complte",
they are still there, doesn't change. I suggest you just run on your
system. see if there is conflict.

Regarding your suggestion:
This is not problem now, we just change this definition.

do you mean just "send" and "complete" or all?

#define
UFS_CMD_TRACE_STRINGS                                   \              
          
        EM(UFS_CMD_SEND,        "send_req")                         \  
                                  
        EM(UFS_CMD_COMP,        "complete_rsp")                     \  

below also need add "req" and "rsp"?

                                  
        EM(UFS_DEV_COMP,        "dev_complete_rsp")                 \  
                                  
        EM(UFS_QUERY_SEND,      "query_send")                   \      
                              
        EM(UFS_QUERY_COMP,      "query_complete")               \      
                              
        EM(UFS_QUERY_ERR,       "query_complete_err")           \      
                              
        EM(UFS_TM_SEND,         "tm_send")                      \      
                              
        EM(UFS_TM_COMP,         "tm_complete")                  \      
                              
        EM(UFS_TM_ERR,          "tm_complete_err")    


>   
> Also, once the parser can differentiate the new format from the old,
> whatever follows its fine: cdb / osf / tsf or whatever makes sense to
> you.
> 
> Thanks,
> Avri