Messages in this thread | | | From | Grant Coady <> | Subject | Re: 2.6 vs 2.4, ssh terminal slowdown | Date | Wed, 08 Feb 2006 16:39:09 +1100 |
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Hi Willy, On Wed, 8 Feb 2006 06:17:09 +0100, Willy Tarreau <willy@w.ods.org> wrote:
>Hi Grant, > >On Wed, Feb 08, 2006 at 03:51:24PM +1100, Grant Coady wrote: >> On Wed, 8 Feb 2006 14:00:59 +1100, Con Kolivas <kernel@kolivas.org> wrote: >> >> >This is the terminal's fault. xterm et al use an algorithm to determine how >> >fast your machine is and decide whether to jump scroll or smooth scroll. This >> >algorithm is basically broken with the 2.6 scheduler and it decides to mostly >> >smooth scroll. >> >> Strange it does that over localnet to a PuTTY terminal on windoze. >> >> Seems a strange thing to do in the kernel though, presentation >> buffering / management surely can be done in userspace? > >I suspect the sshd on the firewall gets woken up for each line and it >behaves exactly like an xterm. After having done a lot of "ls -l|cat" >on 2.6, I'm not surprized at all :-/ > >A good test would be to strace sshd under 2.4 and 2.6. You could even >use strace -tt. Probably that you will see something like 1 ms between >two reads on 2.6 and nearly nothing between them in 2.4.
Yes, it is nearly 1ms per line delay with 2.6, but 2.4 and 2.6 with the trailing '|cat' give similar times, didn't try that notion last time.
We know now it isn't the network cards, disk I/O, just an oddness in 2.6 ;)
Cheers, Grant. - 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/
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