From 1bf4af165050d90ea6659ffb2536ec8ca783aab5 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Mon, 26 Oct 2009 18:47:42 +0000 Subject: powerpc: tracing: Add powerpc tracepoints for interrupt entry and exit This adds powerpc-specific tracepoints for interrupt entry and exit. While we already have generic irq_handler_entry and irq_handler_exit tracepoints there are cases on our virtualised powerpc machines where an interrupt is presented to the OS, but subsequently handled by the hypervisor. This means no OS interrupt handler is invoked. Here is an example on a POWER6 machine with the patch below applied: -0 [006] 3243.949840744: irq_entry: pt_regs=c0000000ce31fb10 -0 [006] 3243.949850520: irq_exit: pt_regs=c0000000ce31fb10 -0 [007] 3243.950218208: irq_entry: pt_regs=c0000000ce323b10 -0 [007] 3243.950224080: irq_exit: pt_regs=c0000000ce323b10 -0 [000] 3244.021879320: irq_entry: pt_regs=c000000000a63aa0 -0 [000] 3244.021883616: irq_handler_entry: irq=87 handler=eth0 -0 [000] 3244.021887328: irq_handler_exit: irq=87 return=handled -0 [000] 3244.021897408: irq_exit: pt_regs=c000000000a63aa0 Here we see two phantom interrupts (no handler was invoked), followed by a real interrupt for eth0. Without the tracepoints in this patch we would have missed the phantom interrupts. Signed-off-by: Anton Blanchard Acked-by: Steven Rostedt Signed-off-by: Paul Mackerras --- arch/powerpc/include/asm/trace.h | 53 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 arch/powerpc/include/asm/trace.h (limited to 'arch/powerpc/include/asm/trace.h') diff --git a/arch/powerpc/include/asm/trace.h b/arch/powerpc/include/asm/trace.h new file mode 100644 index 000000000000..187696da5ae7 --- /dev/null +++ b/arch/powerpc/include/asm/trace.h @@ -0,0 +1,53 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM powerpc + +#if !defined(_TRACE_POWERPC_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_POWERPC_H + +#include + +struct pt_regs; + +TRACE_EVENT(irq_entry, + + TP_PROTO(struct pt_regs *regs), + + TP_ARGS(regs), + + TP_STRUCT__entry( + __field(struct pt_regs *, regs) + ), + + TP_fast_assign( + __entry->regs = regs; + ), + + TP_printk("pt_regs=%p", __entry->regs) +); + +TRACE_EVENT(irq_exit, + + TP_PROTO(struct pt_regs *regs), + + TP_ARGS(regs), + + TP_STRUCT__entry( + __field(struct pt_regs *, regs) + ), + + TP_fast_assign( + __entry->regs = regs; + ), + + TP_printk("pt_regs=%p", __entry->regs) +); + +#endif /* _TRACE_POWERPC_H */ + +#undef TRACE_INCLUDE_PATH +#undef TRACE_INCLUDE_FILE + +#define TRACE_INCLUDE_PATH asm +#define TRACE_INCLUDE_FILE trace + +#include -- cgit v1.2.3 From 6795b85c6a4f690e61e7be31aa150d945c723fb5 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Mon, 26 Oct 2009 18:49:14 +0000 Subject: powerpc: tracing: Add powerpc tracepoints for timer entry and exit We can monitor the effectiveness of our power management of both the kernel and hypervisor by probing the timer interrupt. For example, on this box we see 10.37s timer interrupts on an idle core: -0 [010] 3900.671297: timer_interrupt_entry: pt_regs=c0000000ce1e7b10 -0 [010] 3900.671302: timer_interrupt_exit: pt_regs=c0000000ce1e7b10 -0 [010] 3911.042963: timer_interrupt_entry: pt_regs=c0000000ce1e7b10 -0 [010] 3911.042968: timer_interrupt_exit: pt_regs=c0000000ce1e7b10 -0 [010] 3921.414630: timer_interrupt_entry: pt_regs=c0000000ce1e7b10 -0 [010] 3921.414635: timer_interrupt_exit: pt_regs=c0000000ce1e7b10 Since we have a 207MHz decrementer it will go negative and fire every 10.37s even if Linux is completely idle. Signed-off-by: Anton Blanchard Signed-off-by: Paul Mackerras --- arch/powerpc/include/asm/trace.h | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'arch/powerpc/include/asm/trace.h') diff --git a/arch/powerpc/include/asm/trace.h b/arch/powerpc/include/asm/trace.h index 187696da5ae7..b558c31d409e 100644 --- a/arch/powerpc/include/asm/trace.h +++ b/arch/powerpc/include/asm/trace.h @@ -42,6 +42,40 @@ TRACE_EVENT(irq_exit, TP_printk("pt_regs=%p", __entry->regs) ); +TRACE_EVENT(timer_interrupt_entry, + + TP_PROTO(struct pt_regs *regs), + + TP_ARGS(regs), + + TP_STRUCT__entry( + __field(struct pt_regs *, regs) + ), + + TP_fast_assign( + __entry->regs = regs; + ), + + TP_printk("pt_regs=%p", __entry->regs) +); + +TRACE_EVENT(timer_interrupt_exit, + + TP_PROTO(struct pt_regs *regs), + + TP_ARGS(regs), + + TP_STRUCT__entry( + __field(struct pt_regs *, regs) + ), + + TP_fast_assign( + __entry->regs = regs; + ), + + TP_printk("pt_regs=%p", __entry->regs) +); + #endif /* _TRACE_POWERPC_H */ #undef TRACE_INCLUDE_PATH -- cgit v1.2.3 From c8cd093a6e9f96ea6b871576fd4e46d7c818bb89 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Mon, 26 Oct 2009 18:50:29 +0000 Subject: powerpc: tracing: Add hypervisor call tracepoints Add hcall_entry and hcall_exit tracepoints. This replaces the inline assembly HCALL_STATS code and converts it to use the new tracepoints. To keep the disabled case as quick as possible, we embed a status word in the TOC so we can get at it with a single load. By doing so we keep the overhead at a minimum. Time taken for a null hcall: No tracepoint code: 135.79 cycles Disabled tracepoints: 137.95 cycles For reference, before this patch enabling HCALL_STATS resulted in a null hcall of 201.44 cycles! Signed-off-by: Anton Blanchard Signed-off-by: Paul Mackerras --- arch/powerpc/include/asm/trace.h | 45 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'arch/powerpc/include/asm/trace.h') diff --git a/arch/powerpc/include/asm/trace.h b/arch/powerpc/include/asm/trace.h index b558c31d409e..9b01c0e43b55 100644 --- a/arch/powerpc/include/asm/trace.h +++ b/arch/powerpc/include/asm/trace.h @@ -76,6 +76,51 @@ TRACE_EVENT(timer_interrupt_exit, TP_printk("pt_regs=%p", __entry->regs) ); +#ifdef CONFIG_PPC_PSERIES +extern void hcall_tracepoint_regfunc(void); +extern void hcall_tracepoint_unregfunc(void); + +TRACE_EVENT_FN(hcall_entry, + + TP_PROTO(unsigned long opcode), + + TP_ARGS(opcode), + + TP_STRUCT__entry( + __field(unsigned long, opcode) + ), + + TP_fast_assign( + __entry->opcode = opcode; + ), + + TP_printk("opcode=%lu", __entry->opcode), + + hcall_tracepoint_regfunc, hcall_tracepoint_unregfunc +); + +TRACE_EVENT_FN(hcall_exit, + + TP_PROTO(unsigned long opcode, unsigned long retval), + + TP_ARGS(opcode, retval), + + TP_STRUCT__entry( + __field(unsigned long, opcode) + __field(unsigned long, retval) + ), + + TP_fast_assign( + __entry->opcode = opcode; + __entry->retval = retval; + ), + + TP_printk("opcode=%lu retval=%lu", __entry->opcode, __entry->retval), + + hcall_tracepoint_regfunc, hcall_tracepoint_unregfunc +); +#endif + #endif /* _TRACE_POWERPC_H */ #undef TRACE_INCLUDE_PATH -- cgit v1.2.3 From 6f26353ca29e96475208bce673efb6a2c58b73f2 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Mon, 26 Oct 2009 18:51:09 +0000 Subject: powerpc: tracing: Give hypervisor call tracepoints access to arguments While most users of the hcall tracepoints will only want the opcode and return code, some will want all the arguments. To avoid the complexity of using varargs we pass a pointer to the register save area, which contains all the arguments. Signed-off-by: Anton Blanchard Signed-off-by: Paul Mackerras --- arch/powerpc/include/asm/trace.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'arch/powerpc/include/asm/trace.h') diff --git a/arch/powerpc/include/asm/trace.h b/arch/powerpc/include/asm/trace.h index 9b01c0e43b55..cbe2297d68b6 100644 --- a/arch/powerpc/include/asm/trace.h +++ b/arch/powerpc/include/asm/trace.h @@ -82,9 +82,9 @@ extern void hcall_tracepoint_unregfunc(void); TRACE_EVENT_FN(hcall_entry, - TP_PROTO(unsigned long opcode), + TP_PROTO(unsigned long opcode, unsigned long *args), - TP_ARGS(opcode), + TP_ARGS(opcode, args), TP_STRUCT__entry( __field(unsigned long, opcode) @@ -101,9 +101,10 @@ TRACE_EVENT_FN(hcall_entry, TRACE_EVENT_FN(hcall_exit, - TP_PROTO(unsigned long opcode, unsigned long retval), + TP_PROTO(unsigned long opcode, unsigned long retval, + unsigned long *retbuf), - TP_ARGS(opcode, retval), + TP_ARGS(opcode, retval, retbuf), TP_STRUCT__entry( __field(unsigned long, opcode) -- cgit v1.2.3