cc66ebe2a9
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
121 lines
4.3 KiB
C
121 lines
4.3 KiB
C
/*-
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* Copyright (c) 1995 Bruce D. Evans.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _MACHINE_MD_VAR_H_
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#define _MACHINE_MD_VAR_H_
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/*
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* Miscellaneous machine-dependent declarations.
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*/
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extern long Maxmem;
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extern u_int atdevbase; /* offset in virtual memory of ISA io mem */
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extern void (*bcopy_vector)(const void *from, void *to, size_t len);
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extern int busdma_swi_pending;
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extern int (*copyin_vector)(const void *udaddr, void *kaddr, size_t len);
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extern int (*copyout_vector)(const void *kaddr, void *udaddr, size_t len);
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extern u_int cpu_exthigh;
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extern u_int cpu_feature;
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extern u_int cpu_fxsr;
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extern u_int cpu_high;
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extern u_int cpu_id;
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extern u_int cpu_procinfo;
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extern char cpu_vendor[];
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extern u_int cyrix_did;
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extern uint16_t *elan_mmcr;
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extern char kstack[];
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#ifdef PC98
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extern int need_pre_dma_flush;
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extern int need_post_dma_flush;
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#endif
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extern void (*ovbcopy_vector)(const void *from, void *to, size_t len);
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extern char sigcode[];
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extern int szsigcode;
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#ifdef COMPAT_FREEBSD4
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extern int szfreebsd4_sigcode;
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#endif
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#ifdef COMPAT_43
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extern int szosigcode;
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#endif
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#ifdef SWTCH_OPTIM_STATS
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extern int stupid_switch;
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extern int swtch_optim_stats;
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extern int tlb_flush_count;
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extern int lazy_flush_count;
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extern int lazy_flush_fixup;
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#ifdef SMP
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extern int lazy_flush_smpfixup;
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extern int lazy_flush_smpipi;
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extern int lazy_flush_smpbadcr3;
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extern int lazy_flush_smpmiss;
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#endif
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#endif
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#ifdef LAZY_SWITCH
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extern int lazy_flush_enable;
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#endif
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typedef void alias_for_inthand_t(u_int cs, u_int ef, u_int esp, u_int ss);
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struct thread;
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struct reg;
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struct fpreg;
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struct dbreg;
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void bcopyb(const void *from, void *to, size_t len);
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void busdma_swi(void);
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void cpu_halt(void);
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void cpu_reset(void);
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void cpu_setregs(void);
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void cpu_switch_load_gs(void) __asm(__STRING(cpu_switch_load_gs));
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void doreti_iret(void) __asm(__STRING(doreti_iret));
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void doreti_iret_fault(void) __asm(__STRING(doreti_iret_fault));
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void doreti_popl_ds(void) __asm(__STRING(doreti_popl_ds));
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void doreti_popl_ds_fault(void) __asm(__STRING(doreti_popl_ds_fault));
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void doreti_popl_es(void) __asm(__STRING(doreti_popl_es));
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void doreti_popl_es_fault(void) __asm(__STRING(doreti_popl_es_fault));
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void doreti_popl_fs(void) __asm(__STRING(doreti_popl_fs));
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void doreti_popl_fs_fault(void) __asm(__STRING(doreti_popl_fs_fault));
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void enable_sse(void);
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void fillw(int /*u_short*/ pat, void *base, size_t cnt);
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void i486_bzero(void *buf, size_t len);
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void i586_bcopy(const void *from, void *to, size_t len);
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void i586_bzero(void *buf, size_t len);
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int i586_copyin(const void *udaddr, void *kaddr, size_t len);
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int i586_copyout(const void *kaddr, void *udaddr, size_t len);
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void i686_pagezero(void *addr);
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void init_AMD_Elan_sc520(void);
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int is_physical_memory(vm_offset_t addr);
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vm_paddr_t kvtop(void *addr);
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void setidt(int idx, alias_for_inthand_t *func, int typ, int dpl, int selec);
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void swi_vm(void *);
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int user_dbreg_trap(void);
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#endif /* !_MACHINE_MD_VAR_H_ */
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