> Date: Fri, 19 Apr 2013 16:17:14 +0400
> From: Alexander Polakov <p...@sdf.org>
>
> Hello?
>
> I've been running with this diff since July without any issues (i386 &
> amd64).
That doesn't make the diff right. I've indicated better ways to fix
the "issue". But I won't have time anytime soon to
investigate/implement them any time soon. Had hope guenther@ would
have had anything to say about why we excessively generate these
signals in the first place.
> * Alexander Polakov <p...@sdf.org> [121213 18:34]:
> > This diff reduces IPI traffic for a case when process A is sending
> > a lot of signals to process B running on a different CPU. userret()
> > delivers all process signals at once, so there is no need to send
> > an interrupt for every signal.
> >
> > The problem was noticed by rtorrent 0.9.2 users, which does exactly
> > this, which led to process/system hangs and slowness.
> >
> > Tested and known to help on amd64 by me and dcoppa@.
> >
> > Index: amd64/amd64/machdep.c
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/amd64/amd64/machdep.c,v
> > retrieving revision 1.155
> > diff -u -r1.155 machdep.c
> > --- amd64/amd64/machdep.c 4 Jun 2012 15:19:47 -0000 1.155
> > +++ amd64/amd64/machdep.c 23 Jul 2012 13:49:40 -0000
> > @@ -690,8 +690,10 @@
> > void
> > signotify(struct proc *p)
> > {
> > - aston(p);
> > - cpu_unidle(p->p_cpu);
> > + if (!isastset(p)) {
> > + aston(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > }
> >
> > #ifdef MULTIPROCESSOR
> > Index: amd64/include/cpu.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/amd64/include/cpu.h,v
> > retrieving revision 1.73
> > diff -u -r1.73 cpu.h
> > --- amd64/include/cpu.h 17 Apr 2012 16:02:33 -0000 1.73
> > +++ amd64/include/cpu.h 23 Jul 2012 13:49:40 -0000
> > @@ -213,6 +213,7 @@
> > #endif
> >
> > #define aston(p) ((p)->p_md.md_astpending = 1)
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> >
> > #define curpcb curcpu()->ci_curpcb
> >
> > Index: hppa/hppa/machdep.c
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/hppa/hppa/machdep.c,v
> > retrieving revision 1.206
> > diff -u -r1.206 machdep.c
> > --- hppa/hppa/machdep.c 21 Jun 2012 00:56:59 -0000 1.206
> > +++ hppa/hppa/machdep.c 23 Jul 2012 13:49:40 -0000
> > @@ -1399,8 +1399,10 @@
> > void
> > signotify(struct proc *p)
> > {
> > - setsoftast(p);
> > - cpu_unidle(p->p_cpu);
> > + if (!isastset(p)) {
> > + setsoftast(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > }
> >
> > /*
> > Index: hppa/include/intr.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/hppa/include/intr.h,v
> > retrieving revision 1.37
> > diff -u -r1.37 intr.h
> > --- hppa/include/intr.h 14 Jan 2011 13:20:06 -0000 1.37
> > +++ hppa/include/intr.h 23 Jul 2012 13:49:40 -0000
> > @@ -157,7 +157,8 @@
> > int hppa_ipi_broadcast(u_long);
> > #endif
> >
> > -#define setsoftast(p) (p->p_md.md_astpending = 1)
> > +#define setsoftast(p) ((p)->p_md.md_astpending = 1)
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> >
> > void *softintr_establish(int, void (*)(void *), void *);
> > void softintr_disestablish(void *);
> > Index: i386/i386/machdep.c
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/i386/i386/machdep.c,v
> > retrieving revision 1.510
> > diff -u -r1.510 machdep.c
> > --- i386/i386/machdep.c 23 May 2012 08:23:43 -0000 1.510
> > +++ i386/i386/machdep.c 23 Jul 2012 13:49:40 -0000
> > @@ -2420,8 +2420,10 @@
> > void
> > signotify(struct proc *p)
> > {
> > - aston(p);
> > - cpu_unidle(p->p_cpu);
> > + if (!isastset(p)) {
> > + aston(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > }
> >
> > #ifdef MULTIPROCESSOR
> > Index: i386/include/cpu.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/i386/include/cpu.h,v
> > retrieving revision 1.122
> > diff -u -r1.122 cpu.h
> > --- i386/include/cpu.h 27 Mar 2012 06:44:01 -0000 1.122
> > +++ i386/include/cpu.h 23 Jul 2012 13:49:41 -0000
> > @@ -226,6 +226,7 @@
> > #endif
> >
> > #define aston(p) ((p)->p_md.md_astpending = 1)
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> >
> > #define curpcb curcpu()->ci_curpcb
> >
> > Index: m88k/include/cpu.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/m88k/include/cpu.h,v
> > retrieving revision 1.54
> > diff -u -r1.54 cpu.h
> > --- m88k/include/cpu.h 25 Oct 2011 18:38:06 -0000 1.54
> > +++ m88k/include/cpu.h 23 Jul 2012 13:49:41 -0000
> > @@ -256,6 +256,7 @@
> > (((struct cpu_info *)(framep)->tf.tf_cpu)->ci_intrdepth > 1)
> >
> > #define aston(p) ((p)->p_md.md_astpending = 1)
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> >
> > /*
> > * This is used during profiling to integrate system time.
> > Index: m88k/m88k/m88k_machdep.c
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/m88k/m88k/m88k_machdep.c,v
> > retrieving revision 1.52
> > diff -u -r1.52 m88k_machdep.c
> > --- m88k/m88k/m88k_machdep.c 23 Mar 2012 15:51:26 -0000 1.52
> > +++ m88k/m88k/m88k_machdep.c 23 Jul 2012 13:49:41 -0000
> > @@ -314,8 +314,10 @@
> > void
> > signotify(struct proc *p)
> > {
> > - aston(p);
> > - cpu_unidle(p->p_cpu);
> > + if (!isastset(p)) {
> > + aston(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > }
> >
> > #ifdef MULTIPROCESSOR
> > Index: macppc/macppc/machdep.c
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/macppc/macppc/machdep.c,v
> > retrieving revision 1.131
> > diff -u -r1.131 machdep.c
> > --- macppc/macppc/machdep.c 29 Aug 2011 20:21:44 -0000 1.131
> > +++ macppc/macppc/machdep.c 23 Jul 2012 13:49:41 -0000
> > @@ -935,8 +935,10 @@
> > void
> > signotify(struct proc *p)
> > {
> > - aston(p);
> > - cpu_unidle(p->p_cpu);
> > + if (!isastset(p)) {
> > + aston(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > }
> >
> > #ifdef MULTIPROCESSOR
> > Index: mips64/include/cpu.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/mips64/include/cpu.h,v
> > retrieving revision 1.83
> > diff -u -r1.83 cpu.h
> > --- mips64/include/cpu.h 14 Jul 2012 19:50:11 -0000 1.83
> > +++ mips64/include/cpu.h 23 Jul 2012 13:49:41 -0000
> > @@ -511,12 +511,20 @@
> > * process as soon as possible.
> > */
> > #ifdef MULTIPROCESSOR
> > -#define signotify(p) (aston(p), cpu_unidle(p->p_cpu))
> > +static __inline void
> > +signotify(struct proc *p)
> > +{
> > + if (!isastset(p)) {
> > + aston(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > +}
> > #else
> > #define signotify(p) aston(p)
> > #endif
> >
> > -#define aston(p) p->p_md.md_astpending = 1
> > +#define aston(p) ((p)->p_md.md_astpending = 1)
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> >
> > #endif /* _KERNEL && !_LOCORE */
> >
> > Index: powerpc/include/cpu.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/powerpc/include/cpu.h,v
> > retrieving revision 1.46
> > diff -u -r1.46 cpu.h
> > --- powerpc/include/cpu.h 28 Sep 2010 20:27:55 -0000 1.46
> > +++ powerpc/include/cpu.h 23 Jul 2012 13:49:41 -0000
> > @@ -155,6 +155,7 @@
> > #define DELAY(n) delay(n)
> >
> > #define aston(p) ((p)->p_md.md_astpending = 1)
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> >
> > /*
> > * Preempt the current process if in interrupt from user mode,
> > Index: sparc64/include/cpu.h
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/sparc64/include/cpu.h,v
> > retrieving revision 1.78
> > diff -u -r1.78 cpu.h
> > --- sparc64/include/cpu.h 6 Jul 2011 22:26:44 -0000 1.78
> > +++ sparc64/include/cpu.h 23 Jul 2012 13:49:41 -0000
> > @@ -226,7 +226,7 @@
> > extern void (*cpu_start_clock)(void);
> >
> > #define aston(p) ((p)->p_md.md_astpending = 1)
> > -
> > +#define isastset(p) ((p)->p_md.md_astpending == 1)
> > /*
> > * Preempt the current process if in interrupt from user mode,
> > * or after the current trap/syscall if in system mode.
> > Index: sparc64/sparc64/machdep.c
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/sparc64/sparc64/machdep.c,v
> > retrieving revision 1.138
> > diff -u -r1.138 machdep.c
> > --- sparc64/sparc64/machdep.c 9 May 2012 18:34:21 -0000 1.138
> > +++ sparc64/sparc64/machdep.c 23 Jul 2012 13:49:42 -0000
> > @@ -613,8 +613,10 @@
> > void
> > signotify(struct proc *p)
> > {
> > - aston(p);
> > - cpu_unidle(p->p_cpu);
> > + if (!isastset(p)) {
> > + aston(p);
> > + cpu_unidle(p->p_cpu);
> > + }
> > }
> >
> > int waittime = -1;
> >
>
> --
> Alexander Polakov | plhk.ru
>
>
