[lkml]   [2002]   [Sep]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: do_gettimeofday vs. rdtsc in the scheduler
   From: James Cleverdon <>
Date: Tue, 17 Sep 2002 15:55:52 -0700

The initial sync was easy, even with variable latencies on cache lines. A
much simplified NTP-ish algorithm works fine. The painful thing was bus
clock drift and programs that foolishly relied on the TSC being the same
between CPUs and between nodes.

This is why the gettimeofday implementation should use the system tick
thing and also any profiling support in the C library should avoid
TSC as well.

For small stretches of code TSC can be used for very precise profiling
but otherwise it is pretty useless by in large.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:52    [W:0.055 / U:0.988 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site