Re: 2.6 vs 2.4, ssh terminal slowdown

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Willy,
On Wed, 8 Feb 2006 06:17:09 +0100, Willy Tarreau <[email protected]> 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 <[email protected]> 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 [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux