Subject: Re: Faster pipes, now with uvm_loan()
To: Anders Magnusson <ragge@ludd.luth.se>
From: John Hawkinson <jhawk@MIT.EDU>
List: tech-kern
Date: 04/29/2001 16:32:33
| > On a VAX?  Probably that darn "calls" instruction :-)
| > 
| It's more likely that it is the time measurement. The smallest measurable
| time difference on a MicroVAX (of that type) is 10mS. Look at these
| ping times, for example:
| 
| PING olivaw.ludd.luth.se (130.240.16.39): 56 data bytes
| 64 bytes from 130.240.16.39: icmp_seq=0 ttl=255 time=29.998 ms
| 64 bytes from 130.240.16.39: icmp_seq=1 ttl=255 time=19.999 ms

That's pretty ugly/misleading. Is there some way for
user-level programs to figure out what the time quantum is,
and perhaps some way for ping to notice and round appropriately?

--jhawk