Thierry Coutelier wrote:
Thierry,
Hello,
I am rate limiting traffic going to some IP addresses using CBQ
(and want to change to HTB sometime).
While testing with different packet sizes I found out that I could go above the
rate limit I set. (even with HTB)
The values I use are: rate: 768kbit weight 77kbit allot 10000 avpkt 1512
I did not change the cell or other parameters.
My root qdisc is set to 40MBit.
With those values I am able to go up to 840kbit/s with packets sizes of 612 or 1224.
With other values it's less except for very low values.
Changing the allot value (If I understood well allot*weight=max packets per round)
it only gets worst (tested with 1000 and 50000).
AVPKT is only used for maxidle so it should not change anything ?
What values should I tweak to have the max rate never exeeded and still be able
to come very near my max-rate using 1460 bytes packets ?
Would HTB be more accruate ?
Thanks for the HELP.
to my knowledge, HTB is more predictable than CBQ and easier to set up.
If you want more accuracy, I suggest you modify a file in the kernel source: include/net/pkt_sched.h
Change the #define for PSCHED_CLOCK_SOURCE from PSCHED_JIFFIES to PSCHED_CPU.
I've read this suggestion on the list but never tried it yet. Note that this is valid only for CPUs that support a TSC (Pentium and up).
Regards,
Stephane
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