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Date:      Tue, 5 Apr 2016 06:37:58 +0000 (UTC)
From:      Alexander Motin <mav@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org
Subject:   svn commit: r297574 - stable/10/sys/dev/ipmi
Message-ID:  <201604050637.u356bwDT085328@repo.freebsd.org>
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Author: mav
Date: Tue Apr  5 06:37:58 2016
New Revision: 297574
URL: https://svnweb.freebsd.org/changeset/base/297574

Log:
  MFC r297179: Optimize IPMI watchdog patting.
  
  Set watchdog timer parameters only when they really need to be changed.
  In other cases just restart the timer with single Reset command instead
  of two (Set and Reset).
  
  From one side this visually reduces amount of CPU time burned in tight
  loop waiting while some slow BMC configures its watchdog hardware, that
  seems to be much more complicated task then just resetting the timer.
  
  From another side on some BMCs those slow Set commands sometimes tend to
  timeout, that leads to noisy log messages and even more CPU time burned,
  so avoiding them can provide even bigger bonuses.

Modified:
  stable/10/sys/dev/ipmi/ipmi.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/dev/ipmi/ipmi.c
==============================================================================
--- stable/10/sys/dev/ipmi/ipmi.c	Tue Apr  5 03:27:33 2016	(r297573)
+++ stable/10/sys/dev/ipmi/ipmi.c	Tue Apr  5 06:37:58 2016	(r297574)
@@ -603,6 +603,20 @@ ipmi_polled_enqueue_request(struct ipmi_
  */
 
 static int
+ipmi_reset_watchdog(struct ipmi_softc *sc)
+{
+	struct ipmi_request *req;
+	int error;
+
+	IPMI_ALLOC_DRIVER_REQUEST(req, IPMI_ADDR(IPMI_APP_REQUEST, 0),
+	    IPMI_RESET_WDOG, 0, 0);
+	error = ipmi_submit_driver_request(sc, req, 0);
+	if (error)
+		device_printf(sc->ipmi_dev, "Failed to reset watchdog\n");
+	return (error);
+}
+
+static int
 ipmi_set_watchdog(struct ipmi_softc *sc, unsigned int sec)
 {
 	struct ipmi_request *req;
@@ -613,7 +627,6 @@ ipmi_set_watchdog(struct ipmi_softc *sc,
 
 	IPMI_ALLOC_DRIVER_REQUEST(req, IPMI_ADDR(IPMI_APP_REQUEST, 0),
 	    IPMI_SET_WDOG, 6, 0);
-
 	if (sec) {
 		req->ir_request[0] = IPMI_SET_WD_TIMER_DONT_STOP
 		    | IPMI_SET_WD_TIMER_SMS_OS;
@@ -630,24 +643,10 @@ ipmi_set_watchdog(struct ipmi_softc *sc,
 		req->ir_request[4] = 0;
 		req->ir_request[5] = 0;
 	}
-
 	error = ipmi_submit_driver_request(sc, req, 0);
 	if (error)
 		device_printf(sc->ipmi_dev, "Failed to set watchdog\n");
-	else if (sec) {
-		IPMI_INIT_DRIVER_REQUEST(req, IPMI_ADDR(IPMI_APP_REQUEST, 0),
-		    IPMI_RESET_WDOG, 0, 0);
-
-		error = ipmi_submit_driver_request(sc, req, 0);
-		if (error)
-			device_printf(sc->ipmi_dev,
-			    "Failed to reset watchdog\n");
-	}
-
 	return (error);
-	/*
-	dump_watchdog(sc);
-	*/
 }
 
 static void
@@ -665,12 +664,24 @@ ipmi_wd_event(void *arg, unsigned int cm
 		timeout = ((uint64_t)1 << cmd) / 1000000000;
 		if (timeout == 0)
 			timeout = 1;
-		e = ipmi_set_watchdog(sc, timeout);
-		if (e == 0) {
-			*error = 0;
-			sc->ipmi_watchdog_active = 1;
-		} else
-			(void)ipmi_set_watchdog(sc, 0);
+		if (timeout != sc->ipmi_watchdog_active) {
+			e = ipmi_set_watchdog(sc, timeout);
+			if (e == 0) {
+				sc->ipmi_watchdog_active = timeout;
+			} else {
+				(void)ipmi_set_watchdog(sc, 0);
+				sc->ipmi_watchdog_active = 0;
+			}
+		}
+		if (sc->ipmi_watchdog_active != 0) {
+			e = ipmi_reset_watchdog(sc);
+			if (e == 0) {
+				*error = 0;
+			} else {
+				(void)ipmi_set_watchdog(sc, 0);
+				sc->ipmi_watchdog_active = 0;
+			}
+		}
 	} else if (atomic_readandclear_int(&sc->ipmi_watchdog_active) != 0) {
 		e = ipmi_set_watchdog(sc, 0);
 		if (e != 0 && cmd == 0)

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