d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Optimize intr_execute_handlers() by combining the pic_disable_source() and

Browse Source 
pic_eoi_source() into one call.  This halves the number of spinlock operations
and indirect function calls in the normal case of handling a normal (ithread)
interrupt.  Optimize the atpic and ioapic drivers to use inlines where
appropriate in supporting the intr_execute_handlers() change.

This knocks 900ns, or roughly 1350 cycles, off of the time spent servicing an
interrupt in the common case on my 1.5GHz P4 uniprocessor system.  SMP systems
likely won't see as much of a gain due to the ioapic being more efficient than
the atpic.  I'll investigate porting this to amd64 soon.

Reviewed by:	jhb
This commit is contained in:
Scott Long 2004-08-02 15:31:10 +00:00
parent 67dab3d6c9
commit 5ba0615c03
4 changed files with 71 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
sys/i386/i386/intr_machdep.c
View File

@ -212,8 +212,7 @@ intr_execute_handlers(struct intsrc *isrc, struct intrframe *iframe)
* For stray and threaded interrupts, we mask and EOI the
* source.
*/
isrc->is_pic->pic_disable_source(isrc);
isrc->is_pic->pic_eoi_source(isrc);
isrc->is_pic->pic_disable_source(isrc, PIC_EOI);
if (ih == NULL)
error = EINVAL;
else

16
sys/i386/i386/io_apic.c
View File

@ -118,7 +118,7 @@ static void ioapic_write(volatile ioapic_t *apic, int reg, u_int val);
static const char *ioapic_bus_string(int bus_type);
static void ioapic_print_vector(struct ioapic_intsrc *intpin);
static void ioapic_enable_source(struct intsrc *isrc);
static void ioapic_disable_source(struct intsrc *isrc);
static void ioapic_disable_source(struct intsrc *isrc, int eoi);
static void ioapic_eoi_source(struct intsrc *isrc);
static void ioapic_enable_intr(struct intsrc *isrc);
static int ioapic_vector(struct intsrc *isrc);
@ -147,6 +147,12 @@ static int mixed_mode_active = 1;
#endif
TUNABLE_INT("hw.apic.mixed_mode", &mixed_mode_active);
static __inline void
_ioapic_eoi_source(struct intsrc *isrc)
{
lapic_eoi();
}
static u_int
ioapic_read(volatile ioapic_t *apic, int reg)
{
@ -224,7 +230,7 @@ ioapic_enable_source(struct intsrc *isrc)
}
static void
ioapic_disable_source(struct intsrc *isrc)
ioapic_disable_source(struct intsrc *isrc, int eoi)
{
struct ioapic_intsrc *intpin = (struct ioapic_intsrc *)isrc;
struct ioapic *io = (struct ioapic *)isrc->is_pic;
@ -239,6 +245,10 @@ ioapic_disable_source(struct intsrc *isrc)
flags);
intpin->io_masked = 1;
}
if (eoi == PIC_EOI)
_ioapic_eoi_source(isrc);
mtx_unlock_spin(&icu_lock);
}
@ -246,7 +256,7 @@ static void
ioapic_eoi_source(struct intsrc *isrc)
{
lapic_eoi();
_ioapic_eoi_source(isrc);
}
/*

8
sys/i386/include/intr_machdep.h
View File

@ -50,7 +50,7 @@ struct intsrc;
*/
struct pic {
void (*pic_enable_source)(struct intsrc *);
void (*pic_disable_source)(struct intsrc *);
void (*pic_disable_source)(struct intsrc *, int);
void (*pic_eoi_source)(struct intsrc *);
void (*pic_enable_intr)(struct intsrc *);
int (*pic_vector)(struct intsrc *);
@ -61,6 +61,12 @@ struct pic {
enum intr_polarity);
};
/* Flags for pic_disable_source() */
enum {
PIC_EOI,
PIC_NO_EOI,
};
/*
* An interrupt source. The upper-layer code uses the PIC methods to
* control a given source. The lower-layer PIC drivers can store additional

71
sys/i386/isa/atpic.c
View File

@ -154,7 +154,7 @@ struct atpic_intsrc {
};
static void atpic_enable_source(struct intsrc *isrc);
static void atpic_disable_source(struct intsrc *isrc);
static void atpic_disable_source(struct intsrc *isrc, int eoi);
static void atpic_eoi_master(struct intsrc *isrc);
static void atpic_eoi_slave(struct intsrc *isrc);
static void atpic_enable_intr(struct intsrc *isrc);
@ -191,6 +191,35 @@ static struct atpic_intsrc atintrs[] = {
CTASSERT(sizeof(atintrs) / sizeof(atintrs[0]) == NUM_ISA_IRQS);
static __inline void
_atpic_eoi_master(struct intsrc *isrc)
{
KASSERT(isrc->is_pic == &atpics[MASTER].at_pic,
("%s: mismatched pic", __func__));
#ifndef AUTO_EOI_1
outb(atpics[MASTER].at_ioaddr, OCW2_EOI);
#endif
}
/*
* The data sheet says no auto-EOI on slave, but it sometimes works.
* So, if AUTO_EOI_2 is enabled, we use it.
*/
static __inline void
_atpic_eoi_slave(struct intsrc *isrc)
{
KASSERT(isrc->is_pic == &atpics[SLAVE].at_pic,
("%s: mismatched pic", __func__));
#ifndef AUTO_EOI_2
outb(atpics[SLAVE].at_ioaddr, OCW2_EOI);
#ifndef AUTO_EOI_1
outb(atpics[MASTER].at_ioaddr, OCW2_EOI);
#endif
#endif
}
static void
atpic_enable_source(struct intsrc *isrc)
{
@ -206,48 +235,48 @@ atpic_enable_source(struct intsrc *isrc)
}
static void
atpic_disable_source(struct intsrc *isrc)
atpic_disable_source(struct intsrc *isrc, int eoi)
{
struct atpic_intsrc *ai = (struct atpic_intsrc *)isrc;
struct atpic *ap = (struct atpic *)isrc->is_pic;
if (ai->at_trigger == INTR_TRIGGER_EDGE)
return;
mtx_lock_spin(&icu_lock);
*ap->at_imen |= IMEN_MASK(ai);
outb(ap->at_ioaddr + ICU_IMR_OFFSET, *ap->at_imen);
if (ai->at_trigger != INTR_TRIGGER_EDGE) {
*ap->at_imen |= IMEN_MASK(ai);
outb(ap->at_ioaddr + ICU_IMR_OFFSET, *ap->at_imen);
}
/*
* Take care to call these functions directly instead of through
* a function pointer. All of the referenced variables should
* still be hot in the cache.
*/
if (eoi == PIC_EOI) {
if (isrc->is_pic == &atpics[MASTER].at_pic)
_atpic_eoi_master(isrc);
else
_atpic_eoi_slave(isrc);
}
mtx_unlock_spin(&icu_lock);
}
static void
atpic_eoi_master(struct intsrc *isrc)
{
KASSERT(isrc->is_pic == &atpics[MASTER].at_pic,
("%s: mismatched pic", __func__));
#ifndef AUTO_EOI_1
mtx_lock_spin(&icu_lock);
outb(atpics[MASTER].at_ioaddr, OCW2_EOI);
_atpic_eoi_master(isrc);
mtx_unlock_spin(&icu_lock);
#endif
}
/*
* The data sheet says no auto-EOI on slave, but it sometimes works.
* So, if AUTO_EOI_2 is enabled, we use it.
*/
static void
atpic_eoi_slave(struct intsrc *isrc)
{
KASSERT(isrc->is_pic == &atpics[SLAVE].at_pic,
("%s: mismatched pic", __func__));
#ifndef AUTO_EOI_2
mtx_lock_spin(&icu_lock);
outb(atpics[SLAVE].at_ioaddr, OCW2_EOI);
#ifndef AUTO_EOI_1
outb(atpics[MASTER].at_ioaddr, OCW2_EOI);
#endif
_atpic_eoi_slave(isrc);
mtx_unlock_spin(&icu_lock);
#endif
}