| Message ID | 1504007201-12904-2-git-send-email-yang.zhang.wz@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 29, 2017 at 11:46:35AM +0000, Yang Zhang wrote: > So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called in > idle path which will polling for a while before we enter the real idle > state. > > In virtualization, idle path includes several heavy operations > includes timer access(LAPIC timer or TSC deadline timer) which will hurt > performance especially for latency intensive workload like message > passing task. The cost is mainly come from the vmexit which is a > hardware context switch between VM and hypervisor. Our solution is to > poll for a while and do not enter real idle path if we can get the > schedule event during polling. > > Poll may cause the CPU waste so we adopt a smart polling mechanism to > reduce the useless poll. > > Signed-off-by: Yang Zhang <yang.zhang.wz@gmail.com> > Signed-off-by: Quan Xu <quan.xu0@gmail.com> > Cc: Jeremy Fitzhardinge <jeremy@goop.org> > Cc: Chris Wright <chrisw@sous-sol.org> > Cc: Alok Kataria <akataria@vmware.com> > Cc: Rusty Russell <rusty@rustcorp.com.au> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: x86@kernel.org > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Andy Lutomirski <luto@kernel.org> > Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> > Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: virtualization@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org Adding xen-devel. Juergen, we really should replace Jeremy's name with xen-devel or your name.. Wasn't there an patch by you that took some of the mainternship over it? > --- > arch/x86/include/asm/paravirt.h | 5 +++++ > arch/x86/include/asm/paravirt_types.h | 6 ++++++ > arch/x86/kernel/paravirt.c | 6 ++++++ > 3 files changed, 17 insertions(+) > > diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h > index 9ccac19..6d46760 100644 > --- a/arch/x86/include/asm/paravirt.h > +++ b/arch/x86/include/asm/paravirt.h > @@ -202,6 +202,11 @@ static inline unsigned long long paravirt_read_pmc(int counter) > > #define rdpmcl(counter, val) ((val) = paravirt_read_pmc(counter)) > > +static inline void paravirt_idle_poll(void) > +{ > + PVOP_VCALL0(pv_idle_ops.poll); > +} > + > static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries) > { > PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries); > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > index 9ffc36b..cf45726 100644 > --- a/arch/x86/include/asm/paravirt_types.h > +++ b/arch/x86/include/asm/paravirt_types.h > @@ -324,6 +324,10 @@ struct pv_lock_ops { > struct paravirt_callee_save vcpu_is_preempted; > } __no_randomize_layout; > > +struct pv_idle_ops { > + void (*poll)(void); > +} __no_randomize_layout; > + > /* This contains all the paravirt structures: we get a convenient > * number for each function using the offset which we use to indicate > * what to patch. */ > @@ -334,6 +338,7 @@ struct paravirt_patch_template { > struct pv_irq_ops pv_irq_ops; > struct pv_mmu_ops pv_mmu_ops; > struct pv_lock_ops pv_lock_ops; > + struct pv_idle_ops pv_idle_ops; > } __no_randomize_layout; > > extern struct pv_info pv_info; > @@ -343,6 +348,7 @@ struct paravirt_patch_template { > extern struct pv_irq_ops pv_irq_ops; > extern struct pv_mmu_ops pv_mmu_ops; > extern struct pv_lock_ops pv_lock_ops; > +extern struct pv_idle_ops pv_idle_ops; > > #define PARAVIRT_PATCH(x) \ > (offsetof(struct paravirt_patch_template, x) / sizeof(void *)) > diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c > index bc0a849..1b5b247 100644 > --- a/arch/x86/kernel/paravirt.c > +++ b/arch/x86/kernel/paravirt.c > @@ -128,6 +128,7 @@ static void *get_call_destination(u8 type) > #ifdef CONFIG_PARAVIRT_SPINLOCKS > .pv_lock_ops = pv_lock_ops, > #endif > + .pv_idle_ops = pv_idle_ops, > }; > return *((void **)&tmpl + type); > } > @@ -312,6 +313,10 @@ struct pv_time_ops pv_time_ops = { > .steal_clock = native_steal_clock, > }; > > +struct pv_idle_ops pv_idle_ops = { > + .poll = paravirt_nop, > +}; > + > __visible struct pv_irq_ops pv_irq_ops = { > .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), > .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), > @@ -471,3 +476,4 @@ struct pv_mmu_ops pv_mmu_ops __ro_after_init = { > EXPORT_SYMBOL (pv_mmu_ops); > EXPORT_SYMBOL_GPL(pv_info); > EXPORT_SYMBOL (pv_irq_ops); > +EXPORT_SYMBOL (pv_idle_ops); > -- > 1.8.3.1 >
On 29/08/17 15:55, Konrad Rzeszutek Wilk wrote: > On Tue, Aug 29, 2017 at 11:46:35AM +0000, Yang Zhang wrote: >> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called in >> idle path which will polling for a while before we enter the real idle >> state. >> >> In virtualization, idle path includes several heavy operations >> includes timer access(LAPIC timer or TSC deadline timer) which will hurt >> performance especially for latency intensive workload like message >> passing task. The cost is mainly come from the vmexit which is a >> hardware context switch between VM and hypervisor. Our solution is to >> poll for a while and do not enter real idle path if we can get the >> schedule event during polling. >> >> Poll may cause the CPU waste so we adopt a smart polling mechanism to >> reduce the useless poll. >> >> Signed-off-by: Yang Zhang <yang.zhang.wz@gmail.com> >> Signed-off-by: Quan Xu <quan.xu0@gmail.com> >> Cc: Jeremy Fitzhardinge <jeremy@goop.org> >> Cc: Chris Wright <chrisw@sous-sol.org> >> Cc: Alok Kataria <akataria@vmware.com> >> Cc: Rusty Russell <rusty@rustcorp.com.au> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: "H. Peter Anvin" <hpa@zytor.com> >> Cc: x86@kernel.org >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Andy Lutomirski <luto@kernel.org> >> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> >> Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> >> Cc: Kees Cook <keescook@chromium.org> >> Cc: virtualization@lists.linux-foundation.org >> Cc: linux-kernel@vger.kernel.org > > Adding xen-devel. > > Juergen, we really should replace Jeremy's name with xen-devel or > your name.. I wouldn't mind being added. What does Jeremy think of being removed? > Wasn't there an patch by you that took some of the > mainternship over it? I added include/linux/hypervisor.h to the PARAVIRT section and offered to maintain it in case the PARAVIRT maintainers didn't want to. Juergen
On 2017/8/29 21:55, Konrad Rzeszutek Wilk wrote: > On Tue, Aug 29, 2017 at 11:46:35AM +0000, Yang Zhang wrote: >> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called in >> idle path which will polling for a while before we enter the real idle >> state. >> >> In virtualization, idle path includes several heavy operations >> includes timer access(LAPIC timer or TSC deadline timer) which will hurt >> performance especially for latency intensive workload like message >> passing task. The cost is mainly come from the vmexit which is a >> hardware context switch between VM and hypervisor. Our solution is to >> poll for a while and do not enter real idle path if we can get the >> schedule event during polling. >> >> Poll may cause the CPU waste so we adopt a smart polling mechanism to >> reduce the useless poll. >> >> Signed-off-by: Yang Zhang <yang.zhang.wz@gmail.com> >> Signed-off-by: Quan Xu <quan.xu0@gmail.com> >> Cc: Jeremy Fitzhardinge <jeremy@goop.org> >> Cc: Chris Wright <chrisw@sous-sol.org> >> Cc: Alok Kataria <akataria@vmware.com> >> Cc: Rusty Russell <rusty@rustcorp.com.au> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: "H. Peter Anvin" <hpa@zytor.com> >> Cc: x86@kernel.org >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Andy Lutomirski <luto@kernel.org> >> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> >> Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> >> Cc: Kees Cook <keescook@chromium.org> >> Cc: virtualization@lists.linux-foundation.org >> Cc: linux-kernel@vger.kernel.org > > Adding xen-devel. > > Juergen, we really should replace Jeremy's name with xen-devel or > your name.. Wasn't there an patch by you that took some of the > mainternship over it? Hi Konard, I didn't test it in Xen side since i don't have the environment but i can add it for Xen in next version if you think it is useful to Xen as well. > >> --- >> arch/x86/include/asm/paravirt.h | 5 +++++ >> arch/x86/include/asm/paravirt_types.h | 6 ++++++ >> arch/x86/kernel/paravirt.c | 6 ++++++ >> 3 files changed, 17 insertions(+) >> >> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h >> index 9ccac19..6d46760 100644 >> --- a/arch/x86/include/asm/paravirt.h >> +++ b/arch/x86/include/asm/paravirt.h >> @@ -202,6 +202,11 @@ static inline unsigned long long paravirt_read_pmc(int counter) >> >> #define rdpmcl(counter, val) ((val) = paravirt_read_pmc(counter)) >> >> +static inline void paravirt_idle_poll(void) >> +{ >> + PVOP_VCALL0(pv_idle_ops.poll); >> +} >> + >> static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries) >> { >> PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries); >> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h >> index 9ffc36b..cf45726 100644 >> --- a/arch/x86/include/asm/paravirt_types.h >> +++ b/arch/x86/include/asm/paravirt_types.h >> @@ -324,6 +324,10 @@ struct pv_lock_ops { >> struct paravirt_callee_save vcpu_is_preempted; >> } __no_randomize_layout; >> >> +struct pv_idle_ops { >> + void (*poll)(void); >> +} __no_randomize_layout; >> + >> /* This contains all the paravirt structures: we get a convenient >> * number for each function using the offset which we use to indicate >> * what to patch. */ >> @@ -334,6 +338,7 @@ struct paravirt_patch_template { >> struct pv_irq_ops pv_irq_ops; >> struct pv_mmu_ops pv_mmu_ops; >> struct pv_lock_ops pv_lock_ops; >> + struct pv_idle_ops pv_idle_ops; >> } __no_randomize_layout; >> >> extern struct pv_info pv_info; >> @@ -343,6 +348,7 @@ struct paravirt_patch_template { >> extern struct pv_irq_ops pv_irq_ops; >> extern struct pv_mmu_ops pv_mmu_ops; >> extern struct pv_lock_ops pv_lock_ops; >> +extern struct pv_idle_ops pv_idle_ops; >> >> #define PARAVIRT_PATCH(x) \ >> (offsetof(struct paravirt_patch_template, x) / sizeof(void *)) >> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c >> index bc0a849..1b5b247 100644 >> --- a/arch/x86/kernel/paravirt.c >> +++ b/arch/x86/kernel/paravirt.c >> @@ -128,6 +128,7 @@ static void *get_call_destination(u8 type) >> #ifdef CONFIG_PARAVIRT_SPINLOCKS >> .pv_lock_ops = pv_lock_ops, >> #endif >> + .pv_idle_ops = pv_idle_ops, >> }; >> return *((void **)&tmpl + type); >> } >> @@ -312,6 +313,10 @@ struct pv_time_ops pv_time_ops = { >> .steal_clock = native_steal_clock, >> }; >> >> +struct pv_idle_ops pv_idle_ops = { >> + .poll = paravirt_nop, >> +}; >> + >> __visible struct pv_irq_ops pv_irq_ops = { >> .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), >> .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), >> @@ -471,3 +476,4 @@ struct pv_mmu_ops pv_mmu_ops __ro_after_init = { >> EXPORT_SYMBOL (pv_mmu_ops); >> EXPORT_SYMBOL_GPL(pv_info); >> EXPORT_SYMBOL (pv_irq_ops); >> +EXPORT_SYMBOL (pv_idle_ops); >> -- >> 1.8.3.1 >>
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 9ccac19..6d46760 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -202,6 +202,11 @@ static inline unsigned long long paravirt_read_pmc(int counter) #define rdpmcl(counter, val) ((val) = paravirt_read_pmc(counter)) +static inline void paravirt_idle_poll(void) +{ + PVOP_VCALL0(pv_idle_ops.poll); +} + static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries) { PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries); diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 9ffc36b..cf45726 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -324,6 +324,10 @@ struct pv_lock_ops { struct paravirt_callee_save vcpu_is_preempted; } __no_randomize_layout; +struct pv_idle_ops { + void (*poll)(void); +} __no_randomize_layout; + /* This contains all the paravirt structures: we get a convenient * number for each function using the offset which we use to indicate * what to patch. */ @@ -334,6 +338,7 @@ struct paravirt_patch_template { struct pv_irq_ops pv_irq_ops; struct pv_mmu_ops pv_mmu_ops; struct pv_lock_ops pv_lock_ops; + struct pv_idle_ops pv_idle_ops; } __no_randomize_layout; extern struct pv_info pv_info; @@ -343,6 +348,7 @@ struct paravirt_patch_template { extern struct pv_irq_ops pv_irq_ops; extern struct pv_mmu_ops pv_mmu_ops; extern struct pv_lock_ops pv_lock_ops; +extern struct pv_idle_ops pv_idle_ops; #define PARAVIRT_PATCH(x) \ (offsetof(struct paravirt_patch_template, x) / sizeof(void *)) diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index bc0a849..1b5b247 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -128,6 +128,7 @@ static void *get_call_destination(u8 type) #ifdef CONFIG_PARAVIRT_SPINLOCKS .pv_lock_ops = pv_lock_ops, #endif + .pv_idle_ops = pv_idle_ops, }; return *((void **)&tmpl + type); } @@ -312,6 +313,10 @@ struct pv_time_ops pv_time_ops = { .steal_clock = native_steal_clock, }; +struct pv_idle_ops pv_idle_ops = { + .poll = paravirt_nop, +}; + __visible struct pv_irq_ops pv_irq_ops = { .save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), .restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), @@ -471,3 +476,4 @@ struct pv_mmu_ops pv_mmu_ops __ro_after_init = { EXPORT_SYMBOL (pv_mmu_ops); EXPORT_SYMBOL_GPL(pv_info); EXPORT_SYMBOL (pv_irq_ops); +EXPORT_SYMBOL (pv_idle_ops);