netdev - Re: [RFC iproute2-next] devlink: display elapsed time during flash update

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Message-ID: <4baf15d7-3e7a-9cf3-16cc-93507d07cf5b@intel.com>
Date:   Tue, 29 Sep 2020 11:45:33 -0700
From:   Jacob Keller <jacob.e.keller@...el.com>
To:     Ido Schimmel <idosch@...sch.org>
Cc:     Jakub Kicinski <kubakici@...pl>, netdev@...r.kernel.org,
        snelson@...sando.io
Subject: Re: [RFC iproute2-next] devlink: display elapsed time during flash
 update



On 9/29/2020 11:07 AM, Ido Schimmel wrote:
> On Tue, Sep 29, 2020 at 10:56:23AM -0700, Jacob Keller wrote:
>>
>>
>> On 9/29/2020 10:18 AM, Jakub Kicinski wrote:
>>> On Mon, 28 Sep 2020 16:49:45 -0700 Jacob Keller wrote:
>>>> For some devices, updating the flash can take significant time during
>>>> operations where no status can meaningfully be reported. This can be
>>>> somewhat confusing to a user who sees devlink appear to hang on the
>>>> terminal waiting for the device to update.
>>>>
>>>> Provide a ticking counter of the time elapsed since the previous status
>>>> message in order to make it clear that the program is not simply stuck.
>>>>
>>>> Do not display this message unless a few seconds have passed since the
>>>> last status update. Additionally, if the previous status notification
>>>> included a timeout, display this as part of the message. If we do not
>>>> receive an error or a new status without that time out, replace it with
>>>> the text "timeout reached".
>>>>
>>>> Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
>>>> ---
>>>> Sending this as an RFC because I doubt this is the best implementation. For
>>>> one, I get a weird display issue where the cursor doesn't always end up on
>>>> the end of line in my shell.. The % display works properly, so I'm not sure
>>>> what's wrong here.
>>>>
>>>> Second, even though select should be timing out every 1/10th of a second for
>>>> screen updates, I don't seem to get that behavior in my test. It takes about
>>>> 8 to 10 seconds for the first elapsed time message to be displayed, and it
>>>> updates really slowly. Is select just not that precise? I even tried using a
>>>> timeout of zero, but this means we refresh way too often and it looks bad. I
>>>> am not sure what is wrong here...
>>>
>>> Strange. Did you strace it? Perhaps it's some form of output buffering?
>>>
>>
>> Haven't yet, just noticed the weird output behavior and timing
>> inconsistency.
> 
> Might be similar to this:
> https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/commit/?id=8e6bce735a132150c23503a55ea0aef55a01425f
> 

Yep, I needed the fflush! That resolved the display issue!

Thanks,
Jake