Slowness on pandaboard after cache "fix"

I’ve noticed that my application newsuk runs much much slower after the pandaboard cache fix on the 11th Jan.
The ROM from 9th seems fine.
The world news section takes 12 seconds as against 6 seconds on the 9th Jan ROM.
I’m assuming the additional time is changefsi processing time, but that’s a random assumption – it could be networking that’s affected I suppose.

It’s to be expected that certain things should be a little bit slower now. But twice as slow does sound a bit disappointing.

Part of me thinks this will be down to my code (the code isn’t fully optimised yet), part of me thinks it will be down to shortcomings in the OS’s memory management (the only situation L2 cache maintenance is required is when remapping memory that was/will be used for hardware IO buffers. But with the current way the OS handles memory we end up performing L2 cache maintenance in a lot of other situations, e.g. whenever memory is remapped during a Wimp task switch)

At some point I’m planning on doing some profiling to discover exactly where time is being spent. Hopefully I’ll get round to it sooner rather than later!

The updates on the ROM from the 21st (i.e. the Perform extra TLB maintenance…. done on the 20th) seems to have sorted it, stability and speed. Nice work!

This fix prompted me to update my ROM image. Unfortunately there is a problem booting.

Not sure when the problem was introduced, I was previously using 5.21 21st April 2014 build

It worked first reboot but every time since I get
…
Acorn SCSIFS

Waiting for boot drive to be ready; press Escape to cancel.

I can get it to boot with:
Escape
*con.files.sdfs
Shift/Ctrl/F12 and selecting Reboot.

Using PandaBoard with CJEMicro’s Power Control module and no Widget.

With no widget, CMOS settngs are stored in the rom. New rom – default settings?

Chris: I believe only the Pi version ‘stores’(reads AND writes) CMOS within the ROM. Though all versions I believe have a default set included.

Tim: We came across this problem on one of our PandaRO’s today. It seems the problem was an out of date !Configure which upon any configuration changes or a shutdown¹ writes a CMOS file only 4 bytes long! Updating to the beta ROM image fixed it (The 5.20 Stable Disk image isn’t enough).

¹ I don’t understand why CMOS is being written to at any time other than when changes are made re Configuration or when the stored year is updated?

I remember having this problem a while back.
As Chris mentioned, you need to update to the latest nightly disk image as well.
There were a lot of changes over the last year, a heck of a lot. ChangeFSI being one of them.
It’s well worth updating.
I seem to remember having a world of pain, updating the disc image and doing a cmos reset, then reconfiguring sorted my issue out.
But it was quite awhile ago when I did it.
Updating !Boot is pretty essential though