Re: Is there a hidden channel in X authentication?

[Pavel Kankovsky <peak () argo troja mff cuni cz>]

On Sun, 27 May 2001 wwieser () gmx de wrote:

> Did you try to insert a usleep(1) before the writev() syscall? This 
> _might_ narrow down the noise as the last timer interrupt is just done when 
> usleep returns (On i386, the time resolution is 1/100s = 10000usec; 
> AFAIK usleep will not sleep shorter than time resolution.) 

Good idea. It eliminated a lot of noise. (Unfortunately it made tests much
slower as well...my computer needed nearly an hour to make 17 x 10000
runs).

The results with usleep(1), 10000 runs per a line.

match.  min        avg       max
bytes
 0      46451      47434     239600
 1      46334      47388     156628
 2      46337      47468     164785
 3      46495      47521     156686
 4      46581      47582     156550
 5      46545      47552     166340
 6      46479      47490     156573
 7      46397      47393     156736
 8      46522      47476     164105
 9      46402      47434     156612
10      46487      47419     157070
11      46412      47446     164578
12      46498      47461     156842
13      46405      47521     156954
14      46485      47494     164273
15      46425      47425     156649
16      46397      47380     156788

--Pavel Kankovsky aka Peak  [ Boycott Microsoft--http://www.vcnet.com/bms ]
"Resistance is futile. Open your source code and prepare for assimilation."