Increasing HZ (patch for HZ > 1000)

[Jean-Marc Valin <Jean-Marc.Valin@USherbrooke.ca>]

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Hi,

I think this may be of interest to some people. I've attached a patch
that makes it possible to increase HZ up to 10000. The patch adds some
HZ-related defines (e.g. SHIFT_HZ) for higher HZ values. It also removes
some shift by negative number and divide by zero (e.g. in bogomips
computation) and prevents some overflows. I'm not sure I fixed
everything, but right now it seems to work with HZ=10000. The only thing
I'm seeing are messages such as: "orinoco_lock() called with
hw_unavailable (dev=f75c8000)" and "eth1: IRQ handler is looping too
much! Resetting.".

I know it's (much) too late for 2.6 but I'm sending the patch anyway so
it (hopefully) doesn't get lost. 

	Jean-Marc

-- 
Jean-Marc Valin, M.Sc.A., ing. jr.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada

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[-- Type: text/x-patch, Size: 7974 bytes --]

--- linux-2.6.0-test11/include/linux/timex.h	2003-11-26 15:42:54.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/timex.h	2003-12-09 14:33:51.000000000 -0500
@@ -77,6 +77,12 @@
 # define SHIFT_HZ	9
 #elif HZ >= 768 && HZ < 1536
 # define SHIFT_HZ	10
+#elif HZ >= 1536 && HZ < 3072
+# define SHIFT_HZ	11
+#elif HZ >= 3072 && HZ < 6144
+# define SHIFT_HZ	12
+#elif HZ >= 6144 && HZ < 12288
+# define SHIFT_HZ	13
 #else
 # error You lose.
 #endif
--- linux-2.6.0-test11/init/main.c	2003-11-26 15:43:09.000000000 -0500
+++ linux-2.6.0-test11-hz/init/main.c	2003-12-09 14:52:24.000000000 -0500
@@ -212,8 +212,8 @@
 
 /* Round the value and print it */	
 	printk("%lu.%02lu BogoMIPS\n",
-		loops_per_jiffy/(500000/HZ),
-		(loops_per_jiffy/(5000/HZ)) % 100);
+		HZ*(loops_per_jiffy>>3)/62500,
+		(HZ*(loops_per_jiffy>>3)/625)%100);
 }
 
 static int __init debug_kernel(char *str)
--- linux-2.6.0-test11/arch/i386/kernel/cpu/proc.c	2003-11-26 15:45:30.000000000 -0500
+++ linux-2.6.0-test11-hz/arch/i386/kernel/cpu/proc.c	2003-12-09 14:54:20.000000000 -0500
@@ -121,8 +121,8 @@
 			seq_printf(m, " %s", x86_cap_flags[i]);
 
 	seq_printf(m, "\nbogomips\t: %lu.%02lu\n\n",
-		     c->loops_per_jiffy/(500000/HZ),
-		     (c->loops_per_jiffy/(5000/HZ)) % 100);
+                     HZ*(c->loops_per_jiffy>>3)/62500,
+                     (HZ*(c->loops_per_jiffy>>3)/625)%100);
 	return 0;
 }
 
--- linux-2.6.0-test11/kernel/timer.c	2003-11-26 15:45:25.000000000 -0500
+++ linux-2.6.0-test11-hz/kernel/timer.c	2003-12-09 14:57:51.000000000 -0500
@@ -561,7 +561,11 @@
 	if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
 	    ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE;
 	time_offset += ltemp;
-	time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+#if SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE > 0
+	    time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+#else
+	    time_adj = -ltemp >> (SHIFT_HZ + SHIFT_UPDATE - SHIFT_SCALE);
+#endif
     } else {
 	ltemp = time_offset;
 	if (!(time_status & STA_FLL))
@@ -569,7 +573,11 @@
 	if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
 	    ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE;
 	time_offset -= ltemp;
-	time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+#if SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE > 0
+	    time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
+#else
+	    time_adj = ltemp >> (SHIFT_HZ + SHIFT_UPDATE - SHIFT_SCALE);
+#endif
     }
 
     /*
--- linux-2.6.0-test11/include/net/tcp.h	2003-11-26 15:43:05.000000000 -0500
+++ linux-2.6.0-test11-hz/include/net/tcp.h	2003-12-09 15:03:50.000000000 -0500
@@ -486,8 +486,8 @@
    so that we select tick to get range about 4 seconds.
  */
 
-#if HZ <= 16 || HZ > 4096
-# error Unsupported: HZ <= 16 or HZ > 4096
+#if HZ <= 16 || HZ > 16384
+# error Unsupported: HZ <= 16 or HZ > 16384
 #elif HZ <= 32
 # define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG)
 #elif HZ <= 64
@@ -502,8 +502,12 @@
 # define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
 #elif HZ <= 2048
 # define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG)
-#else
+#elif HZ <= 4096
 # define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#elif HZ <= 8192
+# define TCP_TW_RECYCLE_TICK (13+2-TCP_TW_RECYCLE_SLOTS_LOG)
+#else
+# define TCP_TW_RECYCLE_TICK (14+2-TCP_TW_RECYCLE_SLOTS_LOG)
 #endif
 
 /*
--- linux-2.6.0-test11/drivers/char/dtlk.c	2003-11-26 15:43:40.000000000 -0500
+++ linux-2.6.0-test11-hz/drivers/char/dtlk.c	2003-12-09 15:25:12.000000000 -0500
@@ -207,7 +207,7 @@
 				   up to 250 usec for the RDY bit to
 				   go nonzero. */
 				for (retries = 0;
-				     retries < loops_per_jiffy / (4000/HZ);
+				     retries < HZ*(loops_per_jiffy>>5)/125;
 				     retries++)
 					if (inb_p(dtlk_port_tts) &
 					    TTS_WRITABLE)
--- linux-2.6.0-test11/include/linux/isicom.h	2003-11-26 15:43:36.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/isicom.h	2003-12-09 15:30:39.000000000 -0500
@@ -147,7 +147,7 @@
 	int			close_delay;
 	unsigned short		channel;
 	unsigned short		status;
-	unsigned short		closing_wait;
+	unsigned int		closing_wait;
 	struct isi_board	* card;
 	struct tty_struct 	* tty;
 	wait_queue_head_t	close_wait;
--- linux-2.6.0-test11/include/linux/hayesesp.h	2003-11-26 15:45:08.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/hayesesp.h	2003-12-09 15:30:50.000000000 -0500
@@ -87,8 +87,8 @@
 	int			stat_flags;
 	int			custom_divisor;
 	int			close_delay;
-	unsigned short		closing_wait;
-	unsigned short		closing_wait2;
+	unsigned int		closing_wait;
+	unsigned int		closing_wait2;
 	int			IER; 	/* Interrupt Enable Register */
 	int			MCR; 	/* Modem control register */
 	unsigned long		event;
--- linux-2.6.0-test11/include/linux/generic_serial.h	2003-11-26 15:45:26.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/generic_serial.h	2003-12-09 15:31:06.000000000 -0500
@@ -42,7 +42,7 @@
   int                     blocked_open;
   struct tty_struct       *tty;
   unsigned long           event;
-  unsigned short          closing_wait;
+  unsigned int          closing_wait;
   int                     close_delay;
   struct real_driver      *rd;
   int                     wakeup_chars;
--- linux-2.6.0-test11/include/linux/cyclades.h	2003-11-26 15:46:06.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/cyclades.h	2003-12-09 15:31:19.000000000 -0500
@@ -581,7 +581,7 @@
 	int			custom_divisor;
 	int                     x_char; /* to be pushed out ASAP */
 	int			close_delay;
-	unsigned short		closing_wait;
+	unsigned int		closing_wait;
 	unsigned long		event;
 	unsigned long		last_active;
 	int			count;	/* # of fd on device */
--- linux-2.6.0-test11/include/linux/serialP.h	2003-11-26 15:42:57.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/serialP.h	2003-12-09 15:29:12.000000000 -0500
@@ -47,8 +47,8 @@
 	int	count;
 	u8	*iomem_base;
 	u16	iomem_reg_shift;
-	unsigned short	close_delay;
-	unsigned short	closing_wait; /* time to wait before closing */
+	unsigned int	close_delay;
+	unsigned int	closing_wait; /* time to wait before closing */
 	struct async_icount	icount;	
 	int	io_type;
 	struct async_struct *info;
@@ -69,8 +69,8 @@
 	int			quot;
 	int			x_char;	/* xon/xoff character */
 	int			close_delay;
-	unsigned short		closing_wait;
-	unsigned short		closing_wait2; /* obsolete */
+	unsigned int		closing_wait;
+	unsigned int		closing_wait2; /* obsolete */
 	int			IER; 	/* Interrupt Enable Register */
 	int			MCR; 	/* Modem control register */
 	int			LCR; 	/* Line control register */
--- linux-2.6.0-test11/include/net/irda/ircomm_tty.h	2003-11-26 15:43:37.000000000 -0500
+++ linux-2.6.0-test11-hz/include/net/irda/ircomm_tty.h	2003-12-09 15:28:17.000000000 -0500
@@ -97,8 +97,8 @@
 	struct timer_list watchdog_timer;
 	struct work_struct  tqueue;
 
-        unsigned short    close_delay;
-        unsigned short    closing_wait; /* time to wait before closing */
+        unsigned int    close_delay;
+        unsigned int    closing_wait; /* time to wait before closing */
 
 	int  open_count;
 	int  blocked_open;	/* # of blocked opens */
--- linux-2.6.0-test11/include/linux/serial.h	2003-11-26 15:43:24.000000000 -0500
+++ linux-2.6.0-test11-hz/include/linux/serial.h	2003-12-09 15:27:09.000000000 -0500
@@ -39,12 +39,12 @@
 	int	xmit_fifo_size;
 	int	custom_divisor;
 	int	baud_base;
-	unsigned short	close_delay;
+	unsigned int	close_delay;
 	char	io_type;
 	char	reserved_char[1];
 	int	hub6;
-	unsigned short	closing_wait; /* time to wait before closing */
-	unsigned short	closing_wait2; /* no longer used... */
+	unsigned int	closing_wait; /* time to wait before closing */
+	unsigned int	closing_wait2; /* no longer used... */
 	unsigned char	*iomem_base;
 	unsigned short	iomem_reg_shift;
 	unsigned int	port_high;

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