subject:"\[PATCH 16\/19\] powerpc\: create giveup

Re: [PATCH 16/19] powerpc: create giveup_all()

2015-12-02 Thread Michael Ellerman

On Thu, 2015-10-29 at 11:44 +1100, Anton Blanchard wrote:

> Create a single function that gives everything up (FP, VMX, VSX, SPE).
> Doing this all at once means we only do one MSR write.
> 
> A context switch microbenchmark using yield():
> 
> http://ozlabs.org/~anton/junkcode/context_switch2.c
> 
> ./context_switch2 --test=yield --fp --altivec --vector 0 0
> 
> shows an improvement of 3% on POWER8.
> 
> Signed-off-by: Anton Blanchard 
> ---
>  arch/powerpc/include/asm/switch_to.h |  1 +
>  arch/powerpc/kernel/process.c| 75 
> 
>  arch/powerpc/kvm/book3s_pr.c | 17 +---

books3s_pr.c can be a module, so we need giveup_all() to be EXPORT_SYMBOL.

I'll fix it up on my end.

cheers

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

[PATCH 16/19] powerpc: create giveup_all()

2015-10-28 Thread Anton Blanchard

Create a single function that gives everything up (FP, VMX, VSX, SPE).
Doing this all at once means we only do one MSR write.

A context switch microbenchmark using yield():

http://ozlabs.org/~anton/junkcode/context_switch2.c

./context_switch2 --test=yield --fp --altivec --vector 0 0

shows an improvement of 3% on POWER8.

Signed-off-by: Anton Blanchard 
---
 arch/powerpc/include/asm/switch_to.h |  1 +
 arch/powerpc/kernel/process.c| 75 
 arch/powerpc/kvm/book3s_pr.c | 17 +---
 3 files changed, 63 insertions(+), 30 deletions(-)

diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index 9414dcb..8f85678 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -26,6 +26,7 @@ extern void __giveup_vsx(struct task_struct *);
 extern void giveup_vsx(struct task_struct *);
 extern void enable_kernel_spe(void);
 extern void load_up_spe(struct task_struct *);
+extern void giveup_all(struct task_struct *);
 extern void switch_booke_debug_regs(struct debug_reg *new_debug);
 
 #ifdef CONFIG_PPC_FPU
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9f8444b..a1540ee 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -308,6 +308,64 @@ void flush_spe_to_thread(struct task_struct *tsk)
 }
 #endif /* CONFIG_SPE */
 
+static unsigned long msr_all_available;
+
+static int __init init_msr_all_available(void)
+{
+#ifdef CONFIG_PPC_FPU
+   msr_all_available |= MSR_FP;
+#endif
+#ifdef CONFIG_ALTIVEC
+   if (cpu_has_feature(CPU_FTR_ALTIVEC))
+   msr_all_available |= MSR_VEC;
+#endif
+#ifdef CONFIG_VSX
+   if (cpu_has_feature(CPU_FTR_VSX))
+   msr_all_available |= MSR_VSX;
+#endif
+#ifdef CONFIG_SPE
+   if (cpu_has_feature(CPU_FTR_SPE))
+   msr_all_available |= MSR_SPE;
+#endif
+
+   return 0;
+}
+early_initcall(init_msr_all_available);
+
+void giveup_all(struct task_struct *tsk)
+{
+   unsigned long usermsr;
+
+   if (!tsk->thread.regs)
+   return;
+
+   usermsr = tsk->thread.regs->msr;
+
+   if ((usermsr & msr_all_available) == 0)
+   return;
+
+   msr_check_and_set(msr_all_available);
+
+#ifdef CONFIG_PPC_FPU
+   if (usermsr & MSR_FP)
+   __giveup_fpu(tsk);
+#endif
+#ifdef CONFIG_ALTIVEC
+   if (usermsr & MSR_VEC)
+   __giveup_altivec(tsk);
+#endif
+#ifdef CONFIG_VSX
+   if (usermsr & MSR_VSX)
+   __giveup_vsx(tsk);
+#endif
+#ifdef CONFIG_SPE
+   if (usermsr & MSR_SPE)
+   __giveup_spe(tsk);
+#endif
+
+   msr_check_and_clear(msr_all_available);
+}
+
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 void do_send_trap(struct pt_regs *regs, unsigned long address,
  unsigned long error_code, int signal_code, int breakpt)
@@ -839,21 +897,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
__switch_to_tm(prev);
 
-   if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
-   giveup_fpu(prev);
-#ifdef CONFIG_ALTIVEC
-   if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
-   giveup_altivec(prev);
-#endif /* CONFIG_ALTIVEC */
-#ifdef CONFIG_VSX
-   if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
-   /* VMX and FPU registers are already save here */
-   __giveup_vsx(prev);
-#endif /* CONFIG_VSX */
-#ifdef CONFIG_SPE
-   if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
-   giveup_spe(prev);
-#endif /* CONFIG_SPE */
+   /* Save FPU, Altivec, VSX and SPE state */
+   giveup_all(prev);
 
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
switch_booke_debug_regs(>thread.debug);
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 49f5dad..a78e0e6 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -1490,21 +1490,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, 
struct kvm_vcpu *vcpu)
goto out;
/* interrupts now hard-disabled */
 
-   /* Save FPU state in thread_struct */
-   if (current->thread.regs->msr & MSR_FP)
-   giveup_fpu(current);
-
-#ifdef CONFIG_ALTIVEC
-   /* Save Altivec state in thread_struct */
-   if (current->thread.regs->msr & MSR_VEC)
-   giveup_altivec(current);
-#endif
-
-#ifdef CONFIG_VSX
-   /* Save VSX state in thread_struct */
-   if (current->thread.regs->msr & MSR_VSX)
-   __giveup_vsx(current);
-#endif
+   /* Save FPU, Altivec and VSX state */
+   giveup_all(current);
 
/* Preload FPU if it's enabled */
if (kvmppc_get_msr(vcpu) & MSR_FP)
-- 
2.5.0

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

[PATCH 16/19] powerpc: create giveup_all()

2015-10-27 Thread Anton Blanchard

Create a single function that gives everything up (FP, VMX, VSX, SPE).
Doing this all at once means we only do one MSR write.

A context switch microbenchmark using yield():

http://ozlabs.org/~anton/junkcode/context_switch2.c

./context_switch2 --test=yield --fp --altivec --vector 0 0

shows an improvement of 3% on POWER8.

Signed-off-by: Anton Blanchard 
---
 arch/powerpc/include/asm/switch_to.h |  1 +
 arch/powerpc/kernel/process.c| 75 
 arch/powerpc/kvm/book3s_pr.c | 17 +---
 3 files changed, 63 insertions(+), 30 deletions(-)

diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index b6a4951..0b4a339 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -27,6 +27,7 @@ extern void giveup_vsx(struct task_struct *);
 extern void enable_kernel_spe(void);
 extern void giveup_spe(struct task_struct *);
 extern void load_up_spe(struct task_struct *);
+extern void giveup_all(struct task_struct *);
 extern void switch_booke_debug_regs(struct debug_reg *new_debug);
 
 #ifdef CONFIG_PPC_FPU
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index cf2d811..5ca416c 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -308,6 +308,64 @@ void flush_spe_to_thread(struct task_struct *tsk)
 }
 #endif /* CONFIG_SPE */
 
+static unsigned long msr_all_available;
+
+static int __init init_msr_all_available(void)
+{
+#ifdef CONFIG_PPC_FPU
+   msr_all_available |= MSR_FP;
+#endif
+#ifdef CONFIG_ALTIVEC
+   if (cpu_has_feature(CPU_FTR_ALTIVEC))
+   msr_all_available |= MSR_VEC;
+#endif
+#ifdef CONFIG_VSX
+   if (cpu_has_feature(CPU_FTR_VSX))
+   msr_all_available |= MSR_VSX;
+#endif
+#ifdef CONFIG_SPE
+   if (cpu_has_feature(CPU_FTR_SPE))
+   msr_all_available |= MSR_SPE;
+#endif
+
+   return 0;
+}
+early_initcall(init_msr_all_available);
+
+void giveup_all(struct task_struct *tsk)
+{
+   unsigned long usermsr;
+
+   if (!tsk->thread.regs)
+   return;
+
+   usermsr = tsk->thread.regs->msr;
+
+   if ((usermsr & msr_all_available) == 0)
+   return;
+
+   msr_check_and_set(msr_all_available);
+
+#ifdef CONFIG_PPC_FPU
+   if (usermsr & MSR_FP)
+   __giveup_fpu(tsk);
+#endif
+#ifdef CONFIG_ALTIVEC
+   if (usermsr & MSR_VEC)
+   __giveup_altivec(tsk);
+#endif
+#ifdef CONFIG_VSX
+   if (usermsr & MSR_VSX)
+   __giveup_vsx(tsk);
+#endif
+#ifdef CONFIG_SPE
+   if (usermsr & MSR_SPE)
+   __giveup_spe(tsk);
+#endif
+
+   msr_check_and_clear(msr_all_available);
+}
+
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 void do_send_trap(struct pt_regs *regs, unsigned long address,
  unsigned long error_code, int signal_code, int breakpt)
@@ -839,21 +897,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
__switch_to_tm(prev);
 
-   if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
-   giveup_fpu(prev);
-#ifdef CONFIG_ALTIVEC
-   if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
-   giveup_altivec(prev);
-#endif /* CONFIG_ALTIVEC */
-#ifdef CONFIG_VSX
-   if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
-   /* VMX and FPU registers are already save here */
-   __giveup_vsx(prev);
-#endif /* CONFIG_VSX */
-#ifdef CONFIG_SPE
-   if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
-   giveup_spe(prev);
-#endif /* CONFIG_SPE */
+   /* Save FPU, Altivec, VSX and SPE state */
+   giveup_all(prev);
 
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
switch_booke_debug_regs(>thread.debug);
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 49f5dad..a78e0e6 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -1490,21 +1490,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, 
struct kvm_vcpu *vcpu)
goto out;
/* interrupts now hard-disabled */
 
-   /* Save FPU state in thread_struct */
-   if (current->thread.regs->msr & MSR_FP)
-   giveup_fpu(current);
-
-#ifdef CONFIG_ALTIVEC
-   /* Save Altivec state in thread_struct */
-   if (current->thread.regs->msr & MSR_VEC)
-   giveup_altivec(current);
-#endif
-
-#ifdef CONFIG_VSX
-   /* Save VSX state in thread_struct */
-   if (current->thread.regs->msr & MSR_VSX)
-   __giveup_vsx(current);
-#endif
+   /* Save FPU, Altivec and VSX state */
+   giveup_all(current);
 
/* Preload FPU if it's enabled */
if (kvmppc_get_msr(vcpu) & MSR_FP)
-- 
2.5.0

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: [PATCH 16/19] powerpc: create giveup_all()

[PATCH 16/19] powerpc: create giveup_all()

[PATCH 16/19] powerpc: create giveup_all()

3 matches

Site Navigation

Mail list logo

Footer information