Added comments about changing HZ to custom values on sparc. Only supported

for sun4c and sun4m machines.  sun4 will only run at the default HZ=100.
Added commented out option for HZ=1000 along with info for GENERIC, SUN4C,
and SUN4M configs.  Added note to SUN4 config warning that HZ is ignored.

4 files changed, 51 insertions, 3 deletions

diff --git a/sys/arch/sparc/conf/GENERIC b/sys/arch/sparc/conf/GENERIC
index bc4ad0330a7..da5816771f3 100644
--- a/sys/arch/sparc/conf/GENERIC
+++ b/sys/arch/sparc/conf/GENERIC
@@ -1,4 +1,4 @@
-#	$OpenBSD: GENERIC,v 1.21 1998/02/26 10:50:13 johns Exp $
+#	$OpenBSD: GENERIC,v 1.22 1998/03/04 12:42:30 johns Exp $
 # 	$NetBSD: GENERIC,v 1.48 1997/08/23 19:19:01 mjacob Exp $
 
 # Machine architecture; required by config(8)
@@ -6,6 +6,7 @@ machine		sparc
 
 include "../../../conf/GENERIC"
 
+
 # Options for variants of the Sun SPARC architecure.
 # At least one is required.
 option		SUN4		# sun4/100, sun4/200, sun4/300
@@ -50,6 +51,20 @@ auxreg0	at obio0				# sun4m
 # Power status and control register found on Sun4m systems
 power0	at obio0
 
+# The system clock (and stat clock) may be set higher than 100 Hz 
+# On sun4c and sun4m systems.  This is useful if you have a speedy
+# machine and need high accuracy timing for real-time oriented applications.
+# Note: running the system clock at a higher rate will cause the kernel
+#       to use proportionally CPU time handling clock interrupts, 
+#       and if set to ridiculously high values may cause problems.
+#
+# Note: sun4 system will only run the clocks at 100 Hz, other values
+#       are ignored. 
+#
+# On sparc, 1000000 modulo HZ must == 0.  If not, a warning is printed 
+#       at boot time, and HZ is reset to 100.
+#option          HZ=1000
+
 # Mostek clock found on 4/300, sun4c, and sun4m systems.
 # The Mostek clock NVRAM is the "eeprom" on sun4/300 systems.
 clock0	at mainbus0				# sun4c
diff --git a/sys/arch/sparc/conf/SUN4 b/sys/arch/sparc/conf/SUN4
index abc105ceb07..61fc47fba02 100644
--- a/sys/arch/sparc/conf/SUN4
+++ b/sys/arch/sparc/conf/SUN4
@@ -1,4 +1,4 @@
-#	$OpenBSD: SUN4,v 1.16 1998/02/26 10:50:24 johns Exp $
+#	$OpenBSD: SUN4,v 1.17 1998/03/04 12:42:25 johns Exp $
 # 	$NetBSD: GENERIC,v 1.28.2.1 1996/07/02 23:55:22 jtc Exp $
 
 # Machine architecture; required by config(8)
@@ -31,6 +31,10 @@ obio0	at mainbus0				# sun4 and sun4m
 vmes0	at mainbus0				# sun4
 vmel0	at mainbus0				# sun4
 
+
+# Note: sun4 system will only run the clocks at 100 Hz, other values
+#       are ignored.  The HZ option has no effect for sun4.
+
 # Mostek clock found on 4/300, sun4c, and sun4m systems.
 # The Mostek clock NVRAM is the "eeprom" on sun4/300 systems.
 clock0	at obio0 addr 0xf2000000		# sun4/300
diff --git a/sys/arch/sparc/conf/SUN4C b/sys/arch/sparc/conf/SUN4C
index 3ab29656530..7efffbae8cf 100644
--- a/sys/arch/sparc/conf/SUN4C
+++ b/sys/arch/sparc/conf/SUN4C
@@ -64,6 +64,21 @@ sbus0	at mainbus0
 
 audioamd0 at mainbus0
 auxreg0	at mainbus0
+
+# The system clock (and stat clock) may be set higher than 100 Hz
+# On sun4c and sun4m systems.  This is useful if you have a speedy
+# machine and need high accuracy timing for real-time oriented applications.
+# Note: running the system clock at a higher rate will cause the kernel
+#       to use proportionally CPU time handling clock interrupts, 
+#       and if set to ridiculously high values may cause problems.
+#
+# Note: sun4 system will only run the clocks at 100 Hz, other values
+#       are ignored.  
+#
+# On sparc, 1000000 modulo HZ must == 0.  If not, a warning is printed 
+#       at boot time, and HZ is reset to 100.
+#option          HZ=1000
+
 clock0	at mainbus0
 #clock0	at obio0 addr 0xf2000000
 #oclock0 at obio0 addr 0xf3000000
diff --git a/sys/arch/sparc/conf/SUN4M b/sys/arch/sparc/conf/SUN4M
index ef5a896a5eb..288d1328122 100644
--- a/sys/arch/sparc/conf/SUN4M
+++ b/sys/arch/sparc/conf/SUN4M
@@ -1,4 +1,4 @@
-#	$OpenBSD: SUN4M,v 1.17 1998/02/26 10:50:30 johns Exp $
+#	$OpenBSD: SUN4M,v 1.18 1998/03/04 12:42:28 johns Exp $
 # 	$NetBSD: GENERIC,v 1.28.2.1 1996/07/02 23:55:22 jtc Exp $
 
 # Machine architecture; required by config(8)
@@ -40,6 +40,20 @@ auxreg0	at obio0				# sun4m
 # Power status and control register found on Sun4m systems
 power0	at obio0
 
+# The system clock (and stat clock) may be set higher than 100 Hz
+# On sun4c and sun4m systems.  This is useful if you have a speedy
+# machine and need high accuracy timing for real-time oriented applications.
+# Note: running the system clock at a higher rate will cause the kernel
+#       to use proportionally CPU time handling clock interrupts, 
+#       and if set to ridiculously high values may cause problems.
+#
+# Note: sun4 system will only run the clocks at 100 Hz, other values
+#       are ignored.  
+#
+# On sparc, 1000000 modulo HZ must == 0.  If not, a warning is printed 
+#       at boot time, and HZ is reset to 100.
+#option          HZ=1000
+
 # Mostek clock found on 4/300, sun4c, and sun4m systems.
 clock0	at obio0				# sun4m