Messages in this thread |  | | | Date | Wed, 06 Mar 2002 11:17:42 -0800 | | From | george anzinger <> | | Subject | Re: [PATCH] 2.5: preemptive kernel on UP |
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Robert Love wrote: > > During 2.5.5-pre, an optimization was made that removed schedule_tail > from UP kernels. This causes the initial preempt_count of a new task, > which starts at 1, to never decrement to zero and thus never become > preemptible. > > Thanks to everyone who pointed out the lousy performance - it took > awhile to find but it should be fixed now. Please comment if not. > > Patch is against 2.5.6-pre2 and is critical for all UP+preempt users.
With out a lot of looking, wouldn't it be easier to just change fork?
-g > > Robert Love > > diff -urN linux-2.5.6-pre2/arch/alpha/kernel/entry.S linux/arch/alpha/kernel/entry.S > --- linux-2.5.6-pre2/arch/alpha/kernel/entry.S Fri Mar 1 17:21:14 2002 > +++ linux/arch/alpha/kernel/entry.S Mon Mar 4 17:49:27 2002 > @@ -495,7 +495,7 @@ > ret $31,($26),1 > .end alpha_switch_to > > -#ifdef CONFIG_SMP > +#ifdef CONFIG_SMP || CONFIG_PREEMPT > .globl ret_from_fork > .align 3 > .ent ret_from_fork > diff -urN linux-2.5.6-pre2/arch/i386/kernel/entry.S linux/arch/i386/kernel/entry.S > --- linux-2.5.6-pre2/arch/i386/kernel/entry.S Tue Feb 19 21:10:58 2002 > +++ linux/arch/i386/kernel/entry.S Mon Mar 4 17:48:32 2002 > @@ -195,7 +195,7 @@ > > > ENTRY(ret_from_fork) > -#if CONFIG_SMP > +#if CONFIG_SMP || CONFIG_PREEMPT > call SYMBOL_NAME(schedule_tail) > #endif > GET_THREAD_INFO(%ebx) > diff -urN linux-2.5.6-pre2/arch/ppc/kernel/entry.S linux/arch/ppc/kernel/entry.S > --- linux-2.5.6-pre2/arch/ppc/kernel/entry.S Tue Feb 19 21:10:59 2002 > +++ linux/arch/ppc/kernel/entry.S Mon Mar 4 17:48:41 2002 > @@ -343,7 +343,7 @@ > > .globl ret_from_fork > ret_from_fork: > -#ifdef CONFIG_SMP > +#ifdef CONFIG_SMP || CONFIG_PREEMPT > bl schedule_tail > #endif > rlwinm r3,r1,0,0,18 > diff -urN linux-2.5.6-pre2/arch/ppc64/kernel/entry.S linux/arch/ppc64/kernel/entry.S > --- linux-2.5.6-pre2/arch/ppc64/kernel/entry.S Tue Feb 19 21:10:53 2002 > +++ linux/arch/ppc64/kernel/entry.S Mon Mar 4 17:52:16 2002 > @@ -311,7 +311,7 @@ > blr > > _GLOBAL(ret_from_fork) > -#ifdef CONFIG_SMP > +#ifdef CONFIG_SMP || CONFIG_PREEMPT > bl .schedule_tail > #endif > clrrdi r4,r1,THREAD_SHIFT > diff -urN linux-2.5.6-pre2/arch/s390/kernel/entry.S linux/arch/s390/kernel/entry.S > --- linux-2.5.6-pre2/arch/s390/kernel/entry.S Tue Feb 19 21:10:57 2002 > +++ linux/arch/s390/kernel/entry.S Mon Mar 4 17:48:12 2002 > @@ -295,7 +295,7 @@ > stosm 24(%r15),0x03 # reenable interrupts > sr %r0,%r0 # child returns 0 > st %r0,SP_R2(%r15) # store return value (change R2 on stack) > -#ifdef CONFIG_SMP > +#ifdef CONFIG_SMP || CONFIG_PREEMPT > l %r1,BASED(.Lschedtail) > la %r14,BASED(sysc_return) > br %r1 # call schedule_tail, return to sysc_return > @@ -896,7 +896,7 @@ > #error .Ltrace: .long syscall_trace > .Lvfork: .long sys_vfork > > -#ifdef CONFIG_SMP > +#ifdef CONFIG_SMP || CONFIG_PREEMPT > .Lschedtail: .long schedule_tail > #endif > > diff -urN linux-2.5.6-pre2/arch/s390x/kernel/entry.S linux/arch/s390x/kernel/entry.S > --- linux-2.5.6-pre2/arch/s390x/kernel/entry.S Tue Feb 19 21:10:58 2002 > +++ linux/arch/s390x/kernel/entry.S Mon Mar 4 17:53:31 2002 > @@ -280,7 +280,7 @@ > GET_CURRENT # load pointer to task_struct to R9 > stosm 48(%r15),0x03 # reenable interrupts > xc SP_R2(8,%r15),SP_R2(%r15) # child returns 0 > -#ifdef CONFIG_SMP > +#ifdef CONFIG_SMP || CONFIG_PREEMPT > larl %r14,sysc_return > jg schedule_tail # return to sysc_return > #else > diff -urN linux-2.5.6-pre2/kernel/sched.c linux/kernel/sched.c > --- linux-2.5.6-pre2/kernel/sched.c Fri Mar 1 17:21:16 2002 > +++ linux/kernel/sched.c Mon Mar 4 17:54:00 2002 > @@ -397,7 +397,7 @@ > p->sleep_avg) / (EXIT_WEIGHT + 1); > } > > -#if CONFIG_SMP > +#if CONFIG_SMP || CONFIG_PREEMPT > asmlinkage void schedule_tail(void) > { > spin_unlock_irq(&this_rq()->lock); > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
-- George george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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