From: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date: Wed, 12 Oct 2005 05:17:38 +0000 (+0000)
Subject: - Make device polling use seperate SYSTIMER instead of hardclock
X-Git-Tag: v2.0.1~5822
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/a327a6db3cda827865f43fbd6b2066b7b97118a0

- Make device polling use seperate SYSTIMER instead of hardclock
- Add "kern.polling.pollhz" sysctl-node/tunable-variable, which can be used to
  set device polling frequency(1 ~ 20000) on a *running* system

Idea-and-Hint-from: dillon
Review-by: dillon, kernel@, submmit@
Test-with: fxp(4)
---

diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
index 07bf5a0561..d1126b9083 100644
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -70,7 +70,7 @@
  *
  *	@(#)kern_clock.c	8.5 (Berkeley) 1/21/94
  * $FreeBSD: src/sys/kern/kern_clock.c,v 1.105.2.10 2002/10/17 13:19:40 maxim Exp $
- * $DragonFly: src/sys/kern/kern_clock.c,v 1.47 2005/10/11 09:59:56 corecode Exp $
+ * $DragonFly: src/sys/kern/kern_clock.c,v 1.48 2005/10/12 05:17:38 sephe Exp $
  */
 
 #include "opt_ntp.h"
@@ -102,8 +102,47 @@
 #endif
 
 #ifdef DEVICE_POLLING
+#ifndef DEVICE_POLLING_FREQ_MAX
+#define DEVICE_POLLING_FREQ_MAX		20000
+#endif
+#define DEVICE_POLLING_FREQ_DEFAULT	1000
+
 extern void init_device_poll(void);
 extern void hardclock_device_poll(void);
+
+static int sysctl_pollhz(SYSCTL_HANDLER_ARGS);
+
+static struct systimer gd0_pollclock;
+static int pollhz = DEVICE_POLLING_FREQ_DEFAULT;
+
+TUNABLE_INT("kern.polling.pollhz", &pollhz);
+SYSCTL_DECL(_kern_polling);
+SYSCTL_PROC(_kern_polling, OID_AUTO, pollhz, CTLTYPE_INT | CTLFLAG_RW,
+	    0, 0, sysctl_pollhz, "I", "Device polling frequency");
+
+static int
+sysctl_pollhz(SYSCTL_HANDLER_ARGS)
+{
+	int error, phz;
+
+	crit_enter();
+	phz = pollhz;
+	crit_exit();
+
+	error = sysctl_handle_int(oidp, &phz, 0, req);
+	if (error || req->newptr == NULL)
+		return error;
+	if (phz <= 0)
+		return EINVAL;
+	else if (phz > DEVICE_POLLING_FREQ_MAX)
+		phz = DEVICE_POLLING_FREQ_MAX;
+
+	crit_enter();
+	pollhz = phz;
+	gd0_pollclock.periodic = sys_cputimer->fromhz(phz);
+	crit_exit();
+	return 0;
+}
 #endif /* DEVICE_POLLING */
 
 static void initclocks (void *dummy);
@@ -194,6 +233,9 @@ SYSCTL_PROC(_kern, OID_AUTO, basetime, CTLTYPE_STRUCT|CTLFLAG_RD, 0, 0,
 static void hardclock(systimer_t info, struct intrframe *frame);
 static void statclock(systimer_t info, struct intrframe *frame);
 static void schedclock(systimer_t info, struct intrframe *frame);
+#ifdef DEVICE_POLLING
+static void pollclock(systimer_t info, struct intrframe *frame);
+#endif
 static void getnanotime_nbt(struct timespec *nbt, struct timespec *tsp);
 
 int	ticks;			/* system master ticks at hz */
@@ -239,6 +281,15 @@ initclocks_pcpu(void)
 	if (gd->gd_cpuid == 0) {
 	    gd->gd_time_seconds = 1;
 	    gd->gd_cpuclock_base = sys_cputimer->count();
+
+#ifdef DEVICE_POLLING
+	    if (pollhz <= 0)
+		pollhz = DEVICE_POLLING_FREQ_DEFAULT;
+	    else if (pollhz > DEVICE_POLLING_FREQ_MAX)
+		pollhz = DEVICE_POLLING_FREQ_MAX;
+
+	    systimer_init_periodic_nq(&gd0_pollclock, pollclock, NULL, pollhz);
+#endif
 	} else {
 	    /* XXX */
 	    gd->gd_time_seconds = globaldata_find(0)->gd_time_seconds;
@@ -363,10 +414,6 @@ hardclock(systimer_t info, struct intrframe *frame)
 
 	    ++ticks;
 
-#ifdef DEVICE_POLLING
-	    hardclock_device_poll();	/* mpsafe, short and quick */
-#endif /* DEVICE_POLLING */
-
 #if 0
 	    if (tco->tc_poll_pps) 
 		tco->tc_poll_pps(tco);
@@ -671,6 +718,14 @@ schedclock(systimer_t info, struct intrframe *frame)
 	}
 }
 
+#ifdef DEVICE_POLLING
+static void
+pollclock(systimer_t info __unused, struct intrframe *frame __unused)
+{
+	hardclock_device_poll();	/* mpsafe, short and quick */
+}
+#endif
+
 /*
  * Compute number of ticks for the specified amount of time.  The 
  * return value is intended to be used in a clock interrupt timed