Re: Supporting new interfaces in phosphor-ipmi-flash

[Troy Lee <troy_lee@aspeedtech.com>]

Hi Andrew,

The 02/15/2021 07:26, Andrew Jeffery wrote:
> 
> 
> On Tue, 9 Feb 2021, at 19:36, Troy Lee wrote:
> > Hi Team,
> > 
> > While I'm evaluating the performance for the design, I notice that the
> > maximum IPMI through/put over KCS / IPMB / LAN is about 120 command per
> > second. Does anyone know where the bottleneck is?
> 
> So a few thoughts:
> 
> There are a some hints on performance profiling in the wiki:
> 
> https://github.com/openbmc/openbmc/wiki/Performance-Profiling-in-OpenBMC
> 
> However, I'd start by inspecting the message timings on D-Bus. You can capture
> the D-Bus traffic on the BMC with:
> 
> ```shell
> # busctl capture > /tmp/dbus.pcap
> ```
> 
> After that, run your image transfer test. Once the transfer completes, stop the
> capture and copy the pcap file off the BMC.
> 
> One approach to analysing the capture is to use Wireshark[1]. However, I've
> found that for this kind of exploratory stuff, scripting the filtering and
> output can give useful results. On that front I've written dbus-pcap:
> 
> https://github.com/openbmc/openbmc-tools/tree/master/dbus-pcap
The tool is very useful, I used to use dbus-monitor and inspect message
traffic by eyes only.

> 
> which can spit out the messages in JSON format if necessary and it takes
> standard D-Bus match rules for filtering as optional positional arguments:
> 
> https://dbus.freedesktop.org/doc/dbus-specification.html#message-bus-routing-match-rules
> 
> If the overhead is not dominated by the IPC on its own, it's probably time to
> start inspecting specific processes with `perf`. The wiki talks a little more
> about that.
> 
> Hope that helps.
> 
> Andrew
> 
> [1] https://www.wireshark.org/

It roughly takes 8ms to process a blobWrite command. I'll see if any thing 
I can help to improve or it is a limitation.

```
# OBMC OEM BlobTransfer blobWrite
1613620034.097539:
CookedMessage(header=CookedHeader(fixed=FixedHeader(endian=108, type=1, flags=0, version=1, length=32, cookie=107), fields=[Field(type=<MessageFieldType.PATH: 1>, data='/xyz/openbmc_project/Ipmi'), Field(type=<MessageFieldType.MEMBER: 3>, data='execute'), Field(type=<MessageFieldType.INTERFACE: 2>, data='xyz.openbmc_project.Ipmi.Server'), Field(type=<MessageFieldType.DESTINATION: 6>, data='xyz.openbmc_project.Ipmi.Host'), Field(type=<MessageFieldType.SIGNATURE: 8>, data='yyyaya{sv}'), Field(type=<MessageFieldType.SENDER: 7>, data=':1.75')]), body=[46, 0, 128, [207, 194, 0, 4, 211, 39, 84, 226, 0, 0, 64, 0, 0, 0, 16, 0], []])

# Cascaded Checking User Priviledge, not sure where it introduced, but
# it shows on every command even with in-band channel
1613620034.097977:
CookedMessage(header=CookedHeader(fixed=FixedHeader(endian=108, type=1, flags=0, version=1, length=10, cookie=224), fields=[Field(type=<MessageFieldType.PATH: 1>, data='/org/freedesktop/DBus'), Field(type=<MessageFieldType.MEMBER: 3>, data='GetConnectionUnixUser'), Field(type=<MessageFieldType.INTERFACE: 2>, data='org.freedesktop.DBus'), Field(type=<MessageFieldType.DESTINATION: 6>, data='org.freedesktop.DBus'), Field(type=<MessageFieldType.SIGNATURE: 8>, data='s'), Field(type=<MessageFieldType.SENDER: 7>, data=':1.72')]), body=[':1.75'])

# Method returns for checking user priviledge
1613620034.098058:
CookedMessage(header=CookedHeader(fixed=FixedHeader(endian=108, type=2, flags=1, version=1, length=4, cookie=4294967295), fields=[Field(type=<MessageFieldType.REPLY_SERIAL: 5>, data=224), Field(type=<MessageFieldType.SENDER: 7>, data='org.freedesktop.DBus'), Field(type=<MessageFieldType.DESTINATION: 6>, data=':1.72'), Field(type=<MessageFieldType.SIGNATURE: 8>, data='u')]), body=[0])

# Method returns for OBMC OEM BlobTransfer blobWrite
1613620034.106147:
CookedMessage(header=CookedHeader(fixed=FixedHeader(endian=108, type=2, flags=1, version=1, length=11, cookie=225), fields=[Field(type=<MessageFieldType.REPLY_SERIAL: 5>, data=107), Field(type=<MessageFieldType.DESTINATION: 6>, data=':1.75'), Field(type=<MessageFieldType.SIGNATURE: 8>, data='(yyyyay)'), Field(type=<MessageFieldType.SENDER: 7>, data=':1.72')]), body=[[47, 0, 128, 0, [207, 194, 0]]])
```

Thanks,
Troy Lee