svn commit: r248442 - projects/counters/share/man/man9

[Eitan Adler]

Author: eadler
Date: Sun Mar 17 20:11:08 2013
New Revision: 248442
URL: http://svnweb.freebsd.org/changeset/base/248442

Log:
  Content and English language changes
  
  Discussed with:	glebius, jilles, kib
  Approved by:	glebius (implicit)

Modified:
  projects/counters/share/man/man9/counter.9

Modified: projects/counters/share/man/man9/counter.9
==============================================================================
--- projects/counters/share/man/man9/counter.9	Sun Mar 17 19:27:14 2013	(r248441)
+++ projects/counters/share/man/man9/counter.9	Sun Mar 17 20:11:08 2013	(r248442)
@@ -99,14 +99,15 @@ Subtract value of
 from
 .Nm
 .Fa cnt .
-The API does not guarantee any protection from underflow.
+The KPI does not guarantee any protection from underflow.
 See
 .Sx IMPLEMENTATION DETAILS .
 .It Fn counter_u64_fetch cnt
 Obtain current snapshot of the data collected in
 .Nm
 .Fa cnt .
-The data obtained is not guaranteed to be precise.
+The data obtained is not guaranteed to reflect the real cumulative
+value for any moment.
 .It Fn counter_u64_zero cnt
 Clear data collected in
 .Nm
@@ -140,8 +141,9 @@ Any write to oid zeroes it.
 .Sh IMPLEMENTATION DETAILS
 On all architectures
 .Nm
-is implemented using per-CPU data fields, that are specially aligned in
-memory, to avoid excessive CPU cache invalidation during updates.
+is implemented using per-CPU data fields that are specially aligned
+in memory, to avoid inter-CPU bus traffic due to shared use
+of the variables between CPUs.
 These are allocated using
 .Va UMA_ZONE_PCPU
 .Xr uma 9