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Index: sys/conf/NOTES
===================================================================
--- sys/conf/NOTES
+++ sys/conf/NOTES
@@ -1047,8 +1047,8 @@
# DUMMYNET enables the "dummynet" bandwidth limiter. You need IPFIREWALL
# as well. See dummynet(4) and ipfw(8) for more info. When you run
-# DUMMYNET it is advisable to also have at least "options HZ=1000" to achieve
-# a smooth scheduling of the traffic.
+# DUMMYNET, HZ should not be lowered from the default 1000 to get smooth
+# response.
options DUMMYNET
# The DEBUGNET option enables a basic debug/panic-time networking API. It
@@ -1237,14 +1237,13 @@
#####################################################################
# CLOCK OPTIONS
-# The granularity of operation is controlled by the kernel option HZ whose
-# default value (1000 on most architectures) means a granularity of 1ms
-# (1s/HZ). Historically, the default was 100, but finer granularity is
-# required for DUMMYNET and other systems on modern hardware. There are
-# reasonable arguments that HZ should, in fact, be 100 still; consider,
-# that reducing the granularity too much might cause excessive overhead in
-# clock interrupt processing, potentially causing ticks to be missed and thus
-# actually reducing the accuracy of operation.
+# The granularity of operation is controlled by the kernel option HZ (default
+# 1000 or 1ms). 4.4BSD and early versions of FreeBSD defaulted 100, but finer
+# granularity is required for DUMMYNET and other systems on modern hardware.
+# Virtual machines guests default to an HZ value of 100 automatically. Lower
+# values produce less overhead at the expense of reduce accuracy in delivery of
+# kernel timeouts. Some limited systems may require this value to be something
+# specific due to limited periodic interrupt hardware granularity.
options HZ=100

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