[LARTC] Patch accurate packet scheduling for ATM/ADSL

[Russell Stuart]

On Wed, 2007-07-25 at 15:14 +0200, Edouard Thuleau wrote:
> I use the patch
> (http://ace-host.stuart.id.au/russell/files/tc/tc-atm/) for accurate
> the packet scheduling on ATM/ADSL link and i think I've found a bug.
> I tried to write to the author but he didn't answer me.

Sorry.  :(  I have now.

> I work on a Linux 2.6.17 with the iproute2-2.6.18-061002 package.
> I change the type of the cell_align char to short of the struct
> tc_ratespec in the file pkt_sched.h (in the include/linux/ directories
> of iproute package and the kernel source) :
> 
> struct tc_ratespec
> {
> 	unsigned char	cell_log;
> 	unsigned char	__reserved;
> 	unsigned short	feature;	/* Always 0 in pre-atm patch kernels */
> -	char		cell_align;	/* Always 0 in pre-atm patch kernels */
> -	unsigned char	__unused;
> +     short		cell_align;	/* Always 0 in pre-atm patch kernels */
> 	unsigned short	mpu;
> 	__u32		rate;
> };
> 
> The results are much better and with my tests, it works very nicely.
> 
> If it can help someone,

I can't see how that would change things as the cell align
always lies within the range -7..0.  The only thing that 
springs to mind is perhaps you aren't using i386, and your 
CPU doesn't sign extend char's???  What CPU are you using?