IPMI SOL performance
Tom Joseph
tomjose at linux.vnet.ibm.com
Tue Mar 20 06:03:55 AEDT 2018
On Tuesday 20 March 2018 12:17 AM, Emily Shaffer wrote:
>
>
> On Mon, Mar 19, 2018 at 9:27 AM Stewart Smith
> <stewart at linux.vnet.ibm.com <mailto:stewart at linux.vnet.ibm.com>> wrote:
>
> Emily Shaffer <emilyshaffer at google.com
> <mailto:emilyshaffer at google.com>> writes:
> >> Is it a possibility to just increase the petitboot timeout? Do
> you have an
> > idea of how much we are missing it by?
>
> Worst case (may be different currently due to improvements in ipmi
> stack) was about 10-15 minutes.
>
> Yikes.
>
>
> We have different issues on the SSH console though, we can end up
> dropping chunks of console output under load (BMC CPU load or high
> console usage).
>
> I think Jeremy can relive the trauma of heading into the TTY
> layer, but
> I wonder if the solution here has something to do with having a
> end-to-end flow control story.
>
> --
> Stewart Smith
> OPAL Architect, IBM.
>
>
> I was looking in the spec and I saw that the packet length for SOL is
> configurable in the session header, but I didn't find the layout for
> the header. It's definitely not configurable past 255B?
Even though character data field is a variable length field, the
accepted character count in the SOL payload is a single byte. It is
based on the accepted character count that console acknowledges to BMC
and offset is changed. That is the 255 character limitation mentioned.
>
> It really doesn't sound like IPMI is well-suited to this task. Tom,
> can you post a proposal for the OEM command you'd like to see, or if
> you've tried one internally?
I haven't tried this option, the OEM option is to bump the accepted
character count field. It will need changes on the clients (like ipmitool).
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