Messages in this thread | | | Date | Mon, 23 Aug 2004 22:56:59 -0500 | From | "K.R. Foley" <> | Subject | Re: [patch] voluntary-preempt-2.6.8.1-P8 |
| |
Lee Revell wrote: > On Mon, 2004-08-23 at 17:01, Ingo Molnar wrote: > > >> - reduce netdev_max_backlog to 8 (Mark H Johnson) >> > > > On my system this setting has absolutely no effect on the skb related > latencies. I tested setting netdev_max_backlog to every power of two > between 1 and 128, and regardless of this setting, I can produce a > 450-600 usec latency with: > > ping -s 65507 -f $DEFAULT_GATEWAY > > Looks like skb_checksum is the problem. Here is one of the traces: > > http://krustophenia.net/testresults.php?dataset=2.6.8.1-P8#/var/www/2.6.8.1-P8/trace14.txt > > Lee > > -
Setting netdev_max_backlog doesn't seem to have any effect for me either.
I get a similar latency when I try to reproduce your result above, ~612 usec. However, my trace is very different than yours:
http://www.cybsft.com/testresults/2.6.8.1-P8/latency_trace3.txt
In fact most any network activity, with the POSSIBLE exception of already open connections, seem to be able to trigger higher latencies. As you can see here:
http://www.cybsft.com/testresults/2.6.8.1-P8/
kr
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |