lkml.org 
[lkml]   [1999]   [Oct]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: Wrong bogomips after plugging in AC power
Date
Vladimir Dergachev wrote:
>
> On Sat, 30 Oct 1999, Scott Marlowe wrote:
> > No, bogomip calculation is too expensive to do during a running kernel. At
>
> yes and no. It is probably too expensive to run every minute - yes.
> But it takes less time than initialization of scsi bus (that happens after
> you do insmod or some error occurs).

Does a SCSI bus initialization hold the complete system? Calculating
bogomips does.

> Face it - changing cpu speed is a _change_ in system configuration.
>
> Also can someone remind me what rdtsc does ? I thought it counted clock
> cycles. The point of bogomips calculation is to find out how many cycles
> in a second there really are.
>
> The other clock source might be memory bus - anyone heard of memory bus
> changing speed on the fly ?

Yes, but not on a PC. On the StrongARM SA-1100 the memory bus speed is
derived from the CPU core speed. Changing the core speed also means that
you have to reprogram the DRAM timing registers.


Erik

--
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands
Phone: +31-15-2785859 Fax: +31-15-2781843 Email J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:54    [W:0.066 / U:1.220 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site