Hi,
I didn't try the patch per se but I put the jtag_add_clocks() call in the
fastdata for loop. Hardcoding the number of clocks.
My major concern at this point is seeing what's the max download speed we can
get out of openOCD.
With the code changed to call jtag_execute_queue in each
mips_ejtag_fastdata_scan I was seeing download speeds of 2k/sec.
The adapter_khz setting seemed to make no difference.
Changing the code to queue it all up and adding the delay clocks I'm only
seeing speeds of 4k/sec. With a higher adapter_khz rate I needed more delay
clocks but the download speed was slower. I found my best was a rate of 5M
with a delay of 20 clocks.
If I consider these calculations:
A 100% efficient FASTDATA probe driver able to sustain the max TCK rate:
1 word/38 tck * 4 bytes/word * 15M tck/sec = 1.6 Mbytes/sec.
A 100% efficient FASTDATA probe driver suffering from a .5ms roundtrip
handshake per FASTDATA transfer:
USB roundtrip .5ms * 15M tck/sec = 7500 tck
1 word/(7500 + 38 tck) * 4 bytes/word * 15M tck/sec = 7.9 Kbytes/sec.
My first method of executing each fastdata access which only achieved 2k/sec
should have been able to be closer to 7.9 K/sec.
When we cue all the accesses up we should be able to get way more than 4k/sec
since we don't have an extra 0.5ms round trip penalty for every 4 bytes. I
would hope we could get closer to 16k/sec or faster.
What type of performance have you seen?
Thanks,
Mindy
From: Salvador Arroyo [mailto:salva...@telecable.es]
Sent: Thursday, March 21, 2013 8:07 AM
To: openocd-devel@lists.sourceforge.net
Subject: Re: [OpenOCD-devel] Does MIPS FASTDATA in 0.6.1 work?
On 03/21/2013 03:04 PM, Mindy Beseler wrote:
Hello again,
Do I need the 977 patch to try the 1196 patch?
Thanks,
Mindy
No, 977 is a different patch and a bit old.
1196 is really a series of patches. If you go to the patch page at
http://openocd.zylin.com/#/c/1196/
you will see that it depends on another patch, clicking on this patch you
can follow the dependencies and take a look at every patch.
With
git fetch http://openocd.zylin.com/openocd refs/changes/96/1196/5 && git
checkout FETCH_HEAD
you apply all the patches, it is the last of the series.
Thanks
Salvador
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