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freebsd-dev/sys/i386/include/smp.h
peter eb7d0d7512 Commit a partial lazy thread switch mechanism for i386. it isn't as lazy 
as it could be and can do with some more cleanup.  Currently its under
options LAZY_SWITCH.  What this does is avoid %cr3 reloads for short
context switches that do not involve another user process.  ie: we can
take an interrupt, switch to a kthread and return to the user without
explicitly flushing the tlb.  However, this isn't as exciting as it could
be, the interrupt overhead is still high and too much blocks on Giant
still.  There are some debug sysctls, for stats and for an on/off switch.

The main problem with doing this has been "what if the process that you're
running on exits while we're borrowing its address space?" - in this case
we use an IPI to give it a kick when we're about to reclaim the pmap.

Its not compiled in unless you add the LAZY_SWITCH option.  I want to fix a
few more things and get some more feedback before turning it on by default.

This is NOT a replacement for Bosko's lazy interrupt stuff.  This was more
meant for the kthread case, while his was for interrupts.  Mine helps a
little for interrupts, but his helps a lot more.

The stats are enabled with options SWTCH_OPTIM_STATS - this has been a
pseudo-option for years, I just added a bunch of stuff to it.

One non-trivial change was to select a new thread before calling
cpu_switch() in the first place.  This allows us to catch the silly
case of doing a cpu_switch() to the current process.  This happens
uncomfortably often.  This simplifies a bit of the asm code in cpu_switch
(no longer have to call choosethread() in the middle).  This has been
implemented on i386 and (thanks to jake) sparc64.  The others will come
soon.  This is actually seperate to the lazy switch stuff.

Glanced at by:  jake, jhb
2003-04-02 23:53:30 +00:00

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/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* $FreeBSD$
*
*/
#ifndef _MACHINE_SMP_H_
#define _MACHINE_SMP_H_
#ifdef _KERNEL
#if defined(SMP) && defined(I386_CPU) && !defined(COMPILING_LINT)
#error SMP not supported with I386_CPU
#endif
#if defined(SMP) && !defined(APIC_IO)
# error APIC_IO required for SMP, add "options APIC_IO" to your config file.
#endif /* SMP && !APIC_IO */
#if defined(SMP) && defined(CPU_DISABLE_CMPXCHG) && !defined(COMPILING_LINT)
#error SMP not supported with CPU_DISABLE_CMPXCHG
#endif
#if defined(SMP) || defined(APIC_IO)
#ifndef LOCORE
/*
* For sending values to POST displays.
* XXX FIXME: where does this really belong, isa.h/isa.c perhaps?
*/
extern int current_postcode; /** XXX currently in mp_machdep.c */
#define POSTCODE(X) current_postcode = (X), \
outb(0x80, current_postcode)
#define POSTCODE_LO(X) current_postcode &= 0xf0, \
current_postcode |= ((X) & 0x0f), \
outb(0x80, current_postcode)
#define POSTCODE_HI(X) current_postcode &= 0x0f, \
current_postcode |= (((X) << 4) & 0xf0), \
outb(0x80, current_postcode)
#include <sys/bus.h> /* XXX */
#include <machine/apic.h>
#include <machine/frame.h>
#include <i386/isa/icu.h>
#include <i386/isa/intr_machdep.h>
/*
* Interprocessor interrupts for SMP.
*/
#define IPI_INVLTLB XINVLTLB_OFFSET
#define IPI_INVLPG XINVLPG_OFFSET
#define IPI_INVLRNG XINVLRNG_OFFSET
#define IPI_LAZYPMAP XLAZYPMAP_OFFSET
#define IPI_RENDEZVOUS XRENDEZVOUS_OFFSET
#define IPI_AST XCPUAST_OFFSET
#define IPI_STOP XCPUSTOP_OFFSET
#define IPI_HARDCLOCK XHARDCLOCK_OFFSET
#define IPI_STATCLOCK XSTATCLOCK_OFFSET
/* global data in mpboot.s */
extern int bootMP_size;
/* functions in mpboot.s */
void bootMP(void);
/* global data in mp_machdep.c */
extern int bsp_apic_ready;
extern int mp_naps;
extern int mp_nbusses;
extern int mp_napics;
extern int mp_picmode;
extern int boot_cpu_id;
extern vm_offset_t cpu_apic_address;
extern vm_offset_t io_apic_address[];
extern u_int32_t cpu_apic_versions[];
extern u_int32_t *io_apic_versions;
extern int cpu_num_to_apic_id[];
extern int io_num_to_apic_id[];
extern int apic_id_to_logical[];
#define APIC_INTMAPSIZE 32
struct apic_intmapinfo {
int ioapic;
int int_pin;
volatile void *apic_address;
int redirindex;
};
extern struct apic_intmapinfo int_to_apicintpin[];
extern struct pcb stoppcbs[];
/* functions in mp_machdep.c */
void i386_mp_probe(void);
u_int mp_bootaddress(u_int);
u_int isa_apic_mask(u_int);
int isa_apic_irq(int);
int pci_apic_irq(int, int, int);
int apic_irq(int, int);
int next_apic_irq(int);
int undirect_isa_irq(int);
int undirect_pci_irq(int);
int apic_bus_type(int);
int apic_src_bus_id(int, int);
int apic_src_bus_irq(int, int);
int apic_int_type(int, int);
int apic_trigger(int, int);
int apic_polarity(int, int);
int mp_grab_cpu_hlt(void);
void assign_apic_irq(int apic, int intpin, int irq);
void revoke_apic_irq(int irq);
void bsp_apic_configure(void);
void init_secondary(void);
void forward_statclock(void);
void forwarded_statclock(struct clockframe frame);
void forward_hardclock(void);
void forwarded_hardclock(struct clockframe frame);
void ipi_selected(u_int cpus, u_int ipi);
void ipi_all(u_int ipi);
void ipi_all_but_self(u_int ipi);
void ipi_self(u_int ipi);
#ifdef APIC_INTR_REORDER
void set_lapic_isrloc(int, int);
#endif /* APIC_INTR_REORDER */
void smp_invlpg(vm_offset_t addr);
void smp_masked_invlpg(u_int mask, vm_offset_t addr);
void smp_invlpg_range(vm_offset_t startva, vm_offset_t endva);
void smp_masked_invlpg_range(u_int mask, vm_offset_t startva,
vm_offset_t endva);
void smp_invltlb(void);
void smp_masked_invltlb(u_int mask);
/* global data in mpapic.c */
extern volatile lapic_t lapic;
extern volatile ioapic_t **ioapic;
/* functions in mpapic.c */
void apic_dump(char*);
void apic_initialize(void);
void imen_dump(void);
int apic_ipi(int, int, int);
int selected_apic_ipi(u_int, int, int);
int io_apic_setup(int);
void io_apic_setup_intpin(int, int);
void io_apic_set_id(int, int);
int io_apic_get_id(int);
int ext_int_setup(int, int);
void set_apic_timer(int);
int read_apic_timer(void);
void u_sleep(int);
u_int io_apic_read(int, int);
void io_apic_write(int, int, u_int);
#endif /* !LOCORE */
#endif /* SMP && !APIC_IO */
#endif /* _KERNEL */
#endif /* _MACHINE_SMP_H_ */
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