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Re: [ts-7000] Re: high resolution timers and real time [2 Attachments]

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Subject: Re: [ts-7000] Re: high resolution timers and real time [2 Attachments]
From: Peter Gammie <>
Date: Sat, 23 Jan 2010 12:12:05 +1100
<*>[Attachment(s) from Peter Gammie included below]

Charles, any anyone interested in hrtimers:

With Andrew's help I managed to build a 2.6.32.3 kernel that seems to work. 
Attached are a config and a patch, based on this:

http://lkml.org/lkml/2009/7/22/119

that enable hrtimers. I've lightly tested it on a ts7260 with 64Mb of memory. I 
loaded the kernel via TFTP with:

load -r -b 0x00218000 -h 192.168.1.1 z
exec -c "console=ttyAM0,115200 
ip=192.168.1.50:192.168.1.1:192.168.1.1:255.255.255.0:ts7200a:eth0:off  
root=/dev/mtdblock1"

(i.e. no special memory options or anything.)

So the routine is to apply Matthieu's patches, then this one. I expect it will 
apply to other kernel versions (specifically 2.6.29.6 if you want -RT) without 
too much bother - but be careful that the Kconfig patch applies to the right 
system type!

As for the clock multiplexing, Charles's suggestion of using just a PREEMPT 
(not RT) kernel results in better behaviour under light periodic load (it 
doesn't flicker while running top on the console) but about the same under 
heavier load (scp'ing a few megabytes via ethernet). I have the CONFIG_NO_HZ 
(tickless) option set, which may or may not do anything in particular...

So, more investigation is required.

Thanks for all your help.

cheers
peter



<*>Attachment(s) from Peter Gammie:


<*> 2 of 2 File(s) 
http://groups.yahoo.com/group/ts-7000/attachments/folder/2051772589/item/list 
  <*> config-2.6.32.3-hrtimers-patched
  <*> ep93xx-clockevents-2.6.32.3-patch

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