Re: No 100 HZ timer!

[Chris Wedgwood]

On Mon, Apr 16, 2001 at 04:45:39PM -0400, Albert D. Cahalan wrote:

    > CLOCK_10MS a wall clock supporting timers with 10 ms resolution (same as
    > linux today). 
    
    Except on the Alpha, and on some ARM systems, etc.
    The HZ constant varies from 10 to 1200.

Or some people use higher values on x86:

cw@charon(cw)$ uptime
 14:13:02 up 11 days, 21:44,  2 users,  load average: 0.00, 0.00, 0.00
cw@charon(cw)$ cat /proc/interrupts
           CPU0
  0: 2106736381          XT-PIC  timer
  1:     187633          XT-PIC  keyboard
  2:          0          XT-PIC  cascade
  7:   94128650          XT-PIC  eth0, usb-uhci, usb-uhci
 10:   18265929          XT-PIC  ide2
 12:    3107415          XT-PIC  PS/2 Mouse
 14:     753375          XT-PIC  via82cxxx
 15:          2          XT-PIC  ide1
NMI:          0
ERR:          0

thats 2048 ticks/sec -- I had to hack the kernel in a couple of
places to make things happy with that, but so far it seems to work.

I also had to hack libproc.so.* -- what a terribly obscure way that
it uses to determine what HZ is defined as!

I know this has ben beaten to death before but can someone tell me:

   - why we cannot export HZ somewhere

   - why is it called HZ, it seems misleading why not something like
     TICKS_PER_SECOND or similar

   - it seems there are a couple of places that assume HZ==100 still,
     or am I just imagining this (ide code, I forget where now)

  --cw