Date: Mon, 15 Nov 2004 14:24:49 -0500 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: current@FreeBSD.org Subject: Re: 6-CURRENT unbelievably slow? Message-ID: <200411151424.49790.jhb@FreeBSD.org> In-Reply-To: <20041111223705.GL582@hub.freebsd.org> References: <Pine.NEB.3.96L.1041110212739.85487A-100000@fledge.watson.org> <1100176749.41935d6d12032@netchild.homeip.net> <20041111223705.GL582@hub.freebsd.org>
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On Thursday 11 November 2004 05:37 pm, Kris Kennaway wrote:
> On Thu, Nov 11, 2004 at 01:39:09PM +0100, Alexander@Leidinger.net wrote:
> > Zitat von Joe Marcus Clarke <marcus@freebsd.org>:
> > > I noticed the interrupt storm detection line in dmesg. In previous
> > > builds, this worked, but it doesn't seem to be taking effect anymore.
> >
> > AFAIK the interrupt storm detection was removed (at least partially).
>
> s/removed/fixed so it doesn't give so many false positives/
>
> (at least partially) ;-)
>
> Talk to jhb..
Please try this patch out and let me know if it does any better:
--- //depot/vendor/freebsd/src/sys/kern/kern_intr.c 2004/11/05 19:15:40
+++ //depot/projects/smpng/sys/kern/kern_intr.c 2004/11/15 19:20:11
@@ -485,7 +485,7 @@
struct intrhand *ih; /* and our interrupt handler chain */
struct thread *td;
struct proc *p;
- int count, warned;
+ int count, warned, storming;
td = curthread;
p = td->td_proc;
@@ -494,6 +494,7 @@
("%s: ithread and proc linkage out of sync", __func__));
count = 0;
warned = 0;
+ storming = 0;
/*
* As long as we have interrupts outstanding, go through the
@@ -549,10 +550,26 @@
}
/*
- * If we detect an interrupt storm, pause with the
- * source masked until the next hardclock tick.
+ * Interrupt storm handling:
+ *
+ * If this interrupt source is currently storming,
+ * then throttle it to only fire the handler once
+ * per clock tick. Each second we go out of storming
+ * mode to see if the storm has subsided.
+ *
+ * If this interrupt source is not currently
+ * storming, but the number of back to back
+ * interrupts exceeds the storm threshold, then
+ * enter storming mode.
*/
- if (intr_storm_threshold != 0 &&
+ if (storming) {
+ tsleep(&count, td->td_priority, "istorm", 1);
+ if (count > hz) {
+ storming = 0;
+ count = 0;
+ } else
+ count++;
+ } else if (intr_storm_threshold != 0 &&
count >= intr_storm_threshold) {
if (!warned) {
printf(
@@ -560,7 +577,7 @@
p->p_comm);
warned = 1;
}
- tsleep(&count, td->td_priority, "istorm", 1);
+ storming = 1;
count = 0;
} else
count++;
@@ -580,6 +597,7 @@
if (!ithd->it_need) {
TD_SET_IWAIT(td);
count = 0;
+ storming = 0;
CTR2(KTR_INTR, "%s: pid %d: done", __func__, p->p_pid);
mi_switch(SW_VOL, NULL);
CTR2(KTR_INTR, "%s: pid %d: resumed", __func__, p->p_pid);
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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