--- clock_gettime.3.orig	2004-08-06 08:59:24.000000000 -0700
+++ clock_gettime.3	2004-08-06 09:16:52.000000000 -0700
@@ -138,6 +138,34 @@
 .SH NOTE
 Most systems require the program be linked with the librt
 library to use these functions.
+.SH NOTE for SMP systems
+The clocks
+.B CLOCK_PROCESS_CPUTIME_ID
+and 
+.B CLOCK_THREAD_CPUTIME_ID
+are realized on many platforms using timers from the CPUs
+(TSC on i386, AR.ITC on Itanium).
+These registers may differ between CPUs and as a consequence
+these clocks may return
+.B bogus results
+if a process is migrated to another CPU.
+.PP
+If the CPUs in an SMP system have different clock sources then
+there is no way to maintain a correlation between the timer registers since
+each CPU will run at a slightly different frequency. If that is the case then
+.I clock_getcpuclockid(0)
+will return
+.B ENOENT
+to signify this condition. The two clocks will then only be useful if it
+can be insured that a process stays on a certain CPU.
+.PP
+The processors in an SMP system do not start all at exactly the same
+time and therefore the timer registers are typically running at an offset.
+Some architectures include code that attempts to limit these offsets on bootup.
+However, the code cannot guarantee to accurately tune the offsets.
+Glibc contains no provisions to deal with these offsets (unlike the Linux
+Kernel). Typically these offsets are small and therefore the effects may be negligible in most cases.
+.PP
 .SH AVAILABILITY
 On POSIX systems on which these functions are available, the symbol
 .B _POSIX_TIMERS