| Message ID | 20170613130557.26315-4-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 771d4304d07f080b6ce751e12f3579cb012a1b22 |
| Headers | show |
On Tue, 13 Jun 2017 23:05:47 +1000 Nicholas Piggin <npiggin@gmail.com> wrote: > diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h > index f06112cf8734..8366bdc69988 100644 > --- a/arch/powerpc/include/asm/hw_irq.h > +++ b/arch/powerpc/include/asm/hw_irq.h > @@ -32,6 +32,7 @@ > #ifndef __ASSEMBLY__ > > extern void __replay_interrupt(unsigned int vector); > +extern void __replay_wakeup_interrupt(unsigned long srr1); > > extern void timer_interrupt(struct pt_regs *); > extern void performance_monitor_exception(struct pt_regs *regs); Oops, just noticed this remnant from an earlier version. Please ignore this hunk. Thanks, Nick
Nicholas Piggin <npiggin@gmail.com> writes: > On Tue, 13 Jun 2017 23:05:47 +1000 > Nicholas Piggin <npiggin@gmail.com> wrote: > >> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h >> index f06112cf8734..8366bdc69988 100644 >> --- a/arch/powerpc/include/asm/hw_irq.h >> +++ b/arch/powerpc/include/asm/hw_irq.h >> @@ -32,6 +32,7 @@ >> #ifndef __ASSEMBLY__ >> >> extern void __replay_interrupt(unsigned int vector); >> +extern void __replay_wakeup_interrupt(unsigned long srr1); >> >> extern void timer_interrupt(struct pt_regs *); >> extern void performance_monitor_exception(struct pt_regs *regs); > > Oops, just noticed this remnant from an earlier version. Please > ignore this hunk. Done. cheers
On Tue, 2017-06-13 at 13:05:47 UTC, Nicholas Piggin wrote: > When the CPU wakes from low power state, it begins at the system reset > interrupt with the exception that caused the wakeup encoded in SRR1. > > Today, powernv idle wakeup ignores the wakeup reason (except a special > case for HMI), and the regular interrupt corresponding to the > exception will fire after the idle wakeup exits. > > Change this to replay the interrupt from the idle wakeup before > interrupts are hard-enabled. > > Test on POWER8 of context_switch selftests benchmark with polling idle > disabled (e.g., always nap, giving cross-CPU IPIs) gives the following > results: > > original wakeup direct > Different threads, same core: 315k/s 264k/s > Different cores: 235k/s 242k/s > > There is a slowdown for doorbell IPI (same core) case because system > reset wakeup does not clear the message and the doorbell interrupt > fires again needlessly. > > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/771d4304d07f080b6ce751e12f3579 cheers
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index f06112cf8734..8366bdc69988 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -32,6 +32,7 @@ #ifndef __ASSEMBLY__ extern void __replay_interrupt(unsigned int vector); +extern void __replay_wakeup_interrupt(unsigned long srr1); extern void timer_interrupt(struct pt_regs *); extern void performance_monitor_exception(struct pt_regs *regs); @@ -130,6 +131,7 @@ static inline bool arch_irq_disabled_regs(struct pt_regs *regs) extern bool prep_irq_for_idle(void); extern bool prep_irq_for_idle_irqsoff(void); +extern void irq_set_pending_from_srr1(unsigned long srr1); #define fini_irq_for_idle_irqsoff() trace_hardirqs_off(); diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index be32cec28107..76224869059d 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -348,6 +348,7 @@ bool prep_irq_for_idle(void) return true; } +#ifdef CONFIG_PPC_BOOK3S /* * This is for idle sequences that return with IRQs off, but the * idle state itself wakes on interrupt. Tell the irq tracer that @@ -379,6 +380,34 @@ bool prep_irq_for_idle_irqsoff(void) } /* + * Take the SRR1 wakeup reason, index into this table to find the + * appropriate irq_happened bit. + */ +static const u8 srr1_to_lazyirq[0x10] = { + 0, 0, 0, + PACA_IRQ_DBELL, + 0, + PACA_IRQ_DBELL, + PACA_IRQ_DEC, + 0, + PACA_IRQ_EE, + PACA_IRQ_EE, + PACA_IRQ_HMI, + 0, 0, 0, 0, 0 }; + +void irq_set_pending_from_srr1(unsigned long srr1) +{ + unsigned int idx = (srr1 & SRR1_WAKEMASK_P8) >> 18; + + /* + * The 0 index (SRR1[42:45]=b0000) must always evaluate to 0, + * so this can be called unconditionally with srr1 wake reason. + */ + local_paca->irq_happened |= srr1_to_lazyirq[idx]; +} +#endif /* CONFIG_PPC_BOOK3S */ + +/* * Force a replay of the external interrupt handler on this CPU. */ void force_external_irq_replay(void) diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c index f188d84d9c59..1028df82cd2f 100644 --- a/arch/powerpc/platforms/powernv/idle.c +++ b/arch/powerpc/platforms/powernv/idle.c @@ -302,7 +302,10 @@ static unsigned long __power7_idle_type(unsigned long type) void power7_idle_type(unsigned long type) { - __power7_idle_type(type); + unsigned long srr1; + + srr1 = __power7_idle_type(type); + irq_set_pending_from_srr1(srr1); } void power7_idle(void) @@ -337,7 +340,10 @@ static unsigned long __power9_idle_type(unsigned long stop_psscr_val, void power9_idle_type(unsigned long stop_psscr_val, unsigned long stop_psscr_mask) { - __power9_idle_type(stop_psscr_val, stop_psscr_mask); + unsigned long srr1; + + srr1 = __power9_idle_type(stop_psscr_val, stop_psscr_mask); + irq_set_pending_from_srr1(srr1); } /*
When the CPU wakes from low power state, it begins at the system reset interrupt with the exception that caused the wakeup encoded in SRR1. Today, powernv idle wakeup ignores the wakeup reason (except a special case for HMI), and the regular interrupt corresponding to the exception will fire after the idle wakeup exits. Change this to replay the interrupt from the idle wakeup before interrupts are hard-enabled. Test on POWER8 of context_switch selftests benchmark with polling idle disabled (e.g., always nap, giving cross-CPU IPIs) gives the following results: original wakeup direct Different threads, same core: 315k/s 264k/s Different cores: 235k/s 242k/s There is a slowdown for doorbell IPI (same core) case because system reset wakeup does not clear the message and the doorbell interrupt fires again needlessly. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/include/asm/hw_irq.h | 2 ++ arch/powerpc/kernel/irq.c | 29 +++++++++++++++++++++++++++++ arch/powerpc/platforms/powernv/idle.c | 10 ++++++++-- 3 files changed, 39 insertions(+), 2 deletions(-)