Date: Wed, 27 Oct 2004 13:52:04 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: obrien@FreeBSD.org Subject: Re: disabling interrupt storm protection Message-ID: <200410271352.04069.jhb@FreeBSD.org> In-Reply-To: <20041022171924.73B3.SHINO@fornext.org> References: <20041022171134.73B1.SHINO@fornext.org> <20041022171924.73B3.SHINO@fornext.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Friday 22 October 2004 04:26 am, Shunsuke SHINOMIYA wrote:
> > Hi,
> > has there been any ways to disable interrupt storm protection from
> > sys/kern/kern_intr.c:1.109?
>
> Don't try sysctl hw.intr_storm_threshold=0. It mask all interrupt
> sources.
Bah, that's supposed to work but I guess bde's enhancements broke it.
Can you try this patch:
--- //depot/vendor/freebsd/src/sys/kern/kern_intr.c 2004/09/05 02:10:52
+++ //depot/projects/smpng/sys/kern/kern_intr.c 2004/10/27 17:41:06
@@ -485,14 +485,22 @@
struct intrhand *ih; /* and our interrupt handler chain */
struct thread *td;
struct proc *p;
+#ifdef HACK
int count, warming, warned;
+#else
+ int count, warned;
+#endif
td = curthread;
p = td->td_proc;
ithd = (struct ithd *)arg; /* point to myself */
KASSERT(ithd->it_td == td && td->td_ithd == ithd,
("%s: ithread and proc linkage out of sync", __func__));
+#ifdef HACK
warming = 10 * intr_storm_threshold;
+#else
+ count = 0;
+#endif
warned = 0;
/*
@@ -514,7 +522,9 @@
CTR4(KTR_INTR, "%s: pid %d: (%s) need=%d", __func__,
p->p_pid, p->p_comm, ithd->it_need);
+#ifdef HACK
count = 0;
+#endif
while (ithd->it_need) {
/*
* Service interrupts. If another interrupt
@@ -548,9 +558,29 @@
if ((ih->ih_flags & IH_MPSAFE) == 0)
mtx_unlock(&Giant);
}
+
+#ifndef HACK
+ /*
+ * If we detect an interrupt storm, pause with the
+ * source masked until the next hardclock tick.
+ */
+ if (intr_storm_threshold != 0 &&
+ count >= intr_storm_threshold) {
+ if (!warned) {
+ printf(
+ "Interrupt storm detected on \"%s\"; throttling interrupt source\n",
+ p->p_comm);
+ warned = 1;
+ }
+ tsleep(&count, td->td_priority, "istorm", 1);
+ count = 0;
+ } else
+ count++;
+#endif
+
if (ithd->it_enable != NULL) {
ithd->it_enable(ithd->it_vector);
-
+#ifdef HACK
/*
* Storm detection needs a delay here
* to see slightly delayed interrupts
@@ -565,8 +595,10 @@
DELAY(1);
--warming;
}
+#endif
}
+#ifdef HACK
/*
* If we detect an interrupt storm, sleep until
* the next hardclock tick. We sleep at the
@@ -574,7 +606,8 @@
* to ensure that we see slightly delayed
* interrupts.
*/
- if (count >= intr_storm_threshold) {
+ if (intr_storm_threshold != 0 &&
+ count >= intr_storm_threshold) {
if (!warned) {
printf(
"Interrupt storm detected on \"%s\"; throttling interrupt source\n",
@@ -598,6 +631,7 @@
count = INT_MAX - 1;
}
count++;
+#endif
}
WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
mtx_assert(&Giant, MA_NOTOWNED);
@@ -610,6 +644,9 @@
mtx_lock_spin(&sched_lock);
if (!ithd->it_need) {
TD_SET_IWAIT(td);
+#ifndef HACK
+ count = 0;
+#endif
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);
First, can you test that your system works with the default threshold, and
second, can you test that setting the threshold to zero disables the storm
detection?
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200410271352.04069.jhb>