Date: Thu, 12 Jul 2001 23:56:58 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: smp@freebsd.org Subject: CPU disabled by loader... Message-ID: <Pine.BSF.4.21.0107122353080.61694-100000@beppo>
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I have a very simple patch for alpha that allows me to disable CPUS at loader
time via the hints mechanism:
Index: mp_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/alpha/alpha/mp_machdep.c,v
retrieving revision 1.22
diff -u -r1.22 mp_machdep.c
--- mp_machdep.c 2001/06/29 11:10:25 1.22
+++ mp_machdep.c 2001/07/13 06:54:12
@@ -37,6 +37,7 @@
#include <sys/pcpu.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
+#include <sys/bus.h>
#include <vm/vm.h>
#include <vm/pmap.h>
@@ -324,7 +325,7 @@
}
void
-cpu_mp_start()
+cpu_mp_start(void)
{
int i;
@@ -335,6 +336,7 @@
("mp_start() called on non-primary CPU"));
all_cpus = 1 << boot_cpu_id;
for (i = 0; i < hwrpb->rpb_pcs_cnt; i++) {
+ int dv;
struct pcs *pcsp;
if (i == boot_cpu_id)
@@ -361,7 +363,12 @@
}
continue;
}
- all_cpus |= 1 << i;
+ dv = 0;
+ if (resource_int_value("cpu", i, "disable", &dv) == 0 && dv) {
+ printf("CPU %d disabled by loader.\n", i);
+ continue;
+ }
+ all_cpus |= (1 << i);
mp_ncpus++;
}
PCPU_SET(other_cpus, all_cpus & ~(1 << boot_cpu_id));
-------------------
This allows me to set
hint.cpu.N.disable="1" (for N=0..M Cpus)
at loader time or in my hints file. This can be desirable for any large SMP
system- you may have a system that has a flakey CPU that you just want to keep
out of the mix, but you don't want to pull the system apart.
I *think* I see how I'd do i386- but I thought I'd ask about this here as a
more general question of utility.
-matt
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