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authorHeiko Carstens <heiko.carstens@de.ibm.com>2005-07-27 11:45:00 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-07-27 16:26:04 -0700
commit99b2d8df1d06f1072a949fc1e01a08b94b084d5f (patch)
treee5be46e9fbee8b68ab1743ef29037c0596a7265f /arch/s390
parent46ee058cdb3abab9313cc9cb9e9927d7672a718c (diff)
downloadop-kernel-dev-99b2d8df1d06f1072a949fc1e01a08b94b084d5f.zip
op-kernel-dev-99b2d8df1d06f1072a949fc1e01a08b94b084d5f.tar.gz
[PATCH] s390: external call performance
The kernel uses the SIGP external call order code to signal other CPUs. When running with dedicated CPUs external calls don't get delivered immediately but within a fixed polling invervall. This can lead to delays where the system appears to do nothing. Replace the SIGP external call order with the SIGP emergency call order since this one gets delivered immediately. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/head.S2
-rw-r--r--arch/s390/kernel/head64.S2
-rw-r--r--arch/s390/kernel/s390_ext.c16
-rw-r--r--arch/s390/kernel/smp.c10
4 files changed, 17 insertions, 13 deletions
diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index fc8bf5e..928ca65 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -765,7 +765,7 @@ _stext: basr %r13,0 # get base
# check control registers
stctl %c0,%c15,0(%r15)
- oi 2(%r15),0x20 # enable sigp external interrupts
+ oi 2(%r15),0x40 # enable sigp emergency signal
oi 0(%r15),0x10 # switch on low address protection
lctl %c0,%c15,0(%r15)
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 28c50bd..10bc592 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -762,7 +762,7 @@ _stext: basr %r13,0 # get base
# check control registers
stctg %c0,%c15,0(%r15)
- oi 6(%r15),0x20 # enable sigp external interrupts
+ oi 6(%r15),0x40 # enable sigp emergency signal
oi 4(%r15),0x10 # switch on low address proctection
lctlg %c0,%c15,0(%r15)
diff --git a/arch/s390/kernel/s390_ext.c b/arch/s390/kernel/s390_ext.c
index 3bdd38e..207bc51 100644
--- a/arch/s390/kernel/s390_ext.c
+++ b/arch/s390/kernel/s390_ext.c
@@ -19,7 +19,6 @@
#include <asm/irq.h>
/*
- * Simple hash strategy: index = code & 0xff;
* ext_int_hash[index] is the start of the list for all external interrupts
* that hash to this index. With the current set of external interrupts
* (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
@@ -27,6 +26,11 @@
*/
ext_int_info_t *ext_int_hash[256] = { 0, };
+static inline int ext_hash(__u16 code)
+{
+ return (code + (code >> 9)) & 0xff;
+}
+
int register_external_interrupt(__u16 code, ext_int_handler_t handler)
{
ext_int_info_t *p;
@@ -37,7 +41,7 @@ int register_external_interrupt(__u16 code, ext_int_handler_t handler)
return -ENOMEM;
p->code = code;
p->handler = handler;
- index = code & 0xff;
+ index = ext_hash(code);
p->next = ext_int_hash[index];
ext_int_hash[index] = p;
return 0;
@@ -52,7 +56,7 @@ int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
return -EINVAL;
p->code = code;
p->handler = handler;
- index = code & 0xff;
+ index = ext_hash(code);
p->next = ext_int_hash[index];
ext_int_hash[index] = p;
return 0;
@@ -63,7 +67,7 @@ int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
ext_int_info_t *p, *q;
int index;
- index = code & 0xff;
+ index = ext_hash(code);
q = NULL;
p = ext_int_hash[index];
while (p != NULL) {
@@ -90,7 +94,7 @@ int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
if (p == NULL || p->code != code || p->handler != handler)
return -EINVAL;
- index = code & 0xff;
+ index = ext_hash(code);
q = ext_int_hash[index];
if (p != q) {
while (q != NULL) {
@@ -120,7 +124,7 @@ void do_extint(struct pt_regs *regs, unsigned short code)
*/
account_ticks(regs);
kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
- index = code & 0xff;
+ index = ext_hash(code);
for (p = ext_int_hash[index]; p; p = p->next) {
if (likely(p->code == code)) {
if (likely(p->handler))
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 642572a..da77f00 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -375,7 +375,7 @@ static void smp_ext_bitcall(int cpu, ec_bit_sig sig)
* Set signaling bit in lowcore of target cpu and kick it
*/
set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
- while(signal_processor(cpu, sigp_external_call) == sigp_busy)
+ while(signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
udelay(10);
}
@@ -394,7 +394,7 @@ static void smp_ext_bitcall_others(ec_bit_sig sig)
* Set signaling bit in lowcore of target cpu and kick it
*/
set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
- while (signal_processor(cpu, sigp_external_call) == sigp_busy)
+ while (signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
udelay(10);
}
}
@@ -751,9 +751,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
unsigned int cpu;
int i;
- /* request the 0x1202 external interrupt */
- if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
- panic("Couldn't request external interrupt 0x1202");
+ /* request the 0x1201 emergency signal external interrupt */
+ if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
+ panic("Couldn't request external interrupt 0x1201");
smp_check_cpus(max_cpus);
memset(lowcore_ptr,0,sizeof(lowcore_ptr));
/*
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