From abf917cd91cbb73952758f9741e2fa65002a48ee Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 25 Jul 2012 07:56:04 +0200 Subject: cputime: Generic on-demand virtual cputime accounting If we want to stop the tick further idle, we need to be able to account the cputime without using the tick. Virtual based cputime accounting solves that problem by hooking into kernel/user boundaries. However implementing CONFIG_VIRT_CPU_ACCOUNTING require low level hooks and involves more overhead. But we already have a generic context tracking subsystem that is required for RCU needs by archs which plan to shut down the tick outside idle. This patch implements a generic virtual based cputime accounting that relies on these generic kernel/user hooks. There are some upsides of doing this: - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING if context tracking is already built (already necessary for RCU in full tickless mode). - We can rely on the generic context tracking subsystem to dynamically (de)activate the hooks, so that we can switch anytime between virtual and tick based accounting. This way we don't have the overhead of the virtual accounting when the tick is running periodically. And one downside: - There is probably more overhead than a native virtual based cputime accounting. But this relies on hooks that are already set anyway. Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Ingo Molnar Cc: Li Zhong Cc: Namhyung Kim Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner --- arch/ia64/kernel/asm-offsets.c | 2 +- arch/ia64/kernel/entry.S | 16 ++++++++-------- arch/ia64/kernel/fsys.S | 4 ++-- arch/ia64/kernel/head.S | 4 ++-- arch/ia64/kernel/ivt.S | 8 ++++---- arch/ia64/kernel/minstate.h | 2 +- arch/ia64/kernel/time.c | 4 ++-- 7 files changed, 20 insertions(+), 20 deletions(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c index a48bd9a..46c9e30 100644 --- a/arch/ia64/kernel/asm-offsets.c +++ b/arch/ia64/kernel/asm-offsets.c @@ -41,7 +41,7 @@ void foo(void) DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count)); -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE DEFINE(TI_AC_STAMP, offsetof(struct thread_info, ac_stamp)); DEFINE(TI_AC_LEAVE, offsetof(struct thread_info, ac_leave)); DEFINE(TI_AC_STIME, offsetof(struct thread_info, ac_stime)); diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S index 6bfd842..7a53530 100644 --- a/arch/ia64/kernel/entry.S +++ b/arch/ia64/kernel/entry.S @@ -724,7 +724,7 @@ GLOBAL_ENTRY(__paravirt_leave_syscall) #endif .global __paravirt_work_processed_syscall; __paravirt_work_processed_syscall: -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE adds r2=PT(LOADRS)+16,r12 MOV_FROM_ITC(pUStk, p9, r22, r19) // fetch time at leave adds r18=TI_FLAGS+IA64_TASK_SIZE,r13 @@ -762,7 +762,7 @@ __paravirt_work_processed_syscall: ld8 r29=[r2],16 // M0|1 load cr.ipsr ld8 r28=[r3],16 // M0|1 load cr.iip -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE (pUStk) add r14=TI_AC_LEAVE+IA64_TASK_SIZE,r13 ;; ld8 r30=[r2],16 // M0|1 load cr.ifs @@ -793,7 +793,7 @@ __paravirt_work_processed_syscall: ld8.fill r1=[r3],16 // M0|1 load r1 (pUStk) mov r17=1 // A ;; -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE (pUStk) st1 [r15]=r17 // M2|3 #else (pUStk) st1 [r14]=r17 // M2|3 @@ -813,7 +813,7 @@ __paravirt_work_processed_syscall: shr.u r18=r19,16 // I0|1 get byte size of existing "dirty" partition COVER // B add current frame into dirty partition & set cr.ifs ;; -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE mov r19=ar.bsp // M2 get new backing store pointer st8 [r14]=r22 // M save time at leave mov f10=f0 // F clear f10 @@ -948,7 +948,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel) adds r16=PT(CR_IPSR)+16,r12 adds r17=PT(CR_IIP)+16,r12 -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE .pred.rel.mutex pUStk,pKStk MOV_FROM_PSR(pKStk, r22, r29) // M2 read PSR now that interrupts are disabled MOV_FROM_ITC(pUStk, p9, r22, r29) // M fetch time at leave @@ -981,7 +981,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel) ;; ld8.fill r12=[r16],16 ld8.fill r13=[r17],16 -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE (pUStk) adds r3=TI_AC_LEAVE+IA64_TASK_SIZE,r18 #else (pUStk) adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18 @@ -989,7 +989,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel) ;; ld8 r20=[r16],16 // ar.fpsr ld8.fill r15=[r17],16 -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE (pUStk) adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18 // deferred #endif ;; @@ -997,7 +997,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel) ld8.fill r2=[r17] (pUStk) mov r17=1 ;; -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE // mmi_ : ld8 st1 shr;; mmi_ : st8 st1 shr;; // mib : mov add br -> mib : ld8 add br // bbb_ : br nop cover;; mbb_ : mov br cover;; diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index e662f17..c4cd45d 100644 --- a/arch/ia64/kernel/fsys.S +++ b/arch/ia64/kernel/fsys.S @@ -529,7 +529,7 @@ GLOBAL_ENTRY(paravirt_fsys_bubble_down) nop.i 0 ;; mov ar.rsc=0 // M2 set enforced lazy mode, pl 0, LE, loadrs=0 -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE MOV_FROM_ITC(p0, p6, r30, r23) // M get cycle for accounting #else nop.m 0 @@ -555,7 +555,7 @@ GLOBAL_ENTRY(paravirt_fsys_bubble_down) cmp.ne pKStk,pUStk=r0,r0 // A set pKStk <- 0, pUStk <- 1 br.call.sptk.many b7=ia64_syscall_setup // B ;; -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE // mov.m r30=ar.itc is called in advance add r16=TI_AC_STAMP+IA64_TASK_SIZE,r2 add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r2 diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S index 4738ff7..9be4e49 100644 --- a/arch/ia64/kernel/head.S +++ b/arch/ia64/kernel/head.S @@ -1073,7 +1073,7 @@ END(ia64_native_sched_clock) sched_clock = ia64_native_sched_clock #endif -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE GLOBAL_ENTRY(cycle_to_cputime) alloc r16=ar.pfs,1,0,0,0 addl r8=THIS_CPU(ia64_cpu_info) + IA64_CPUINFO_NSEC_PER_CYC_OFFSET,r0 @@ -1091,7 +1091,7 @@ GLOBAL_ENTRY(cycle_to_cputime) shrp r8=r9,r8,IA64_NSEC_PER_CYC_SHIFT br.ret.sptk.many rp END(cycle_to_cputime) -#endif /* CONFIG_VIRT_CPU_ACCOUNTING */ +#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ #ifdef CONFIG_IA64_BRL_EMU diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S index fa25689..689ffca 100644 --- a/arch/ia64/kernel/ivt.S +++ b/arch/ia64/kernel/ivt.S @@ -784,7 +784,7 @@ ENTRY(break_fault) (p8) adds r28=16,r28 // A switch cr.iip to next bundle (p9) adds r8=1,r8 // A increment ei to next slot -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE ;; mov b6=r30 // I0 setup syscall handler branch reg early #else @@ -801,7 +801,7 @@ ENTRY(break_fault) // /////////////////////////////////////////////////////////////////////// st1 [r16]=r0 // M2|3 clear current->thread.on_ustack flag -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE MOV_FROM_ITC(p0, p14, r30, r18) // M get cycle for accounting #else mov b6=r30 // I0 setup syscall handler branch reg early @@ -817,7 +817,7 @@ ENTRY(break_fault) cmp.eq p14,p0=r9,r0 // A are syscalls being traced/audited? br.call.sptk.many b7=ia64_syscall_setup // B 1: -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE // mov.m r30=ar.itc is called in advance, and r13 is current add r16=TI_AC_STAMP+IA64_TASK_SIZE,r13 // A add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r13 // A @@ -1043,7 +1043,7 @@ END(ia64_syscall_setup) DBG_FAULT(16) FAULT(16) -#if defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(__IA64_ASM_PARAVIRTUALIZED_NATIVE) +#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(__IA64_ASM_PARAVIRTUALIZED_NATIVE) /* * There is no particular reason for this code to be here, other than * that there happens to be space here that would go unused otherwise. diff --git a/arch/ia64/kernel/minstate.h b/arch/ia64/kernel/minstate.h index d56753a1..cc82a7d 100644 --- a/arch/ia64/kernel/minstate.h +++ b/arch/ia64/kernel/minstate.h @@ -4,7 +4,7 @@ #include "entry.h" #include "paravirt_inst.h" -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE /* read ar.itc in advance, and use it before leaving bank 0 */ #define ACCOUNT_GET_STAMP \ (pUStk) mov.m r20=ar.itc; diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 88a7945..a3a3f5a 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -77,7 +77,7 @@ static struct clocksource clocksource_itc = { }; static struct clocksource *itc_clocksource; -#ifdef CONFIG_VIRT_CPU_ACCOUNTING +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE #include @@ -142,7 +142,7 @@ void vtime_account_idle(struct task_struct *tsk) account_idle_time(vtime_delta(tsk)); } -#endif /* CONFIG_VIRT_CPU_ACCOUNTING */ +#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ static irqreturn_t timer_interrupt (int irq, void *dev_id) -- cgit v1.1