| Message ID | 20091018110109.GJ4808@kryten (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Sun, 2009-10-18 at 22:01 +1100, Anton Blanchard wrote: > Hi Ben, > > > Breaks 6xx_defconfig: > > Yuck. Since the CREATE_TRACE_POINTS stuff appears to need a non trivial number > of includes it might be best just to fold it into one of the tracepoint call > sites like this. > > -- > > This patch 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: > > <idle>-0 [006] 3243.949840744: irq_entry: pt_regs=c0000000ce31fb10 > <idle>-0 [006] 3243.949850520: irq_exit: pt_regs=c0000000ce31fb10 > > <idle>-0 [007] 3243.950218208: irq_entry: pt_regs=c0000000ce323b10 > <idle>-0 [007] 3243.950224080: irq_exit: pt_regs=c0000000ce323b10 > > <idle>-0 [000] 3244.021879320: irq_entry: pt_regs=c000000000a63aa0 > <idle>-0 [000] 3244.021883616: irq_handler_entry: irq=87 handler=eth0 > <idle>-0 [000] 3244.021887328: irq_handler_exit: irq=87 return=handled > <idle>-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. > > Since these would be the first arch specific tracepoints, I'd like to make > sure we agree on naming. The tracepoints live in events/powerpc/*, but I'm > wondering if the tracepoint name should also contain the arch name, eg > powerpc_irq_entry/powerpc_irq_exit. Thoughts? > > Signed-off-by: Anton Blanchard <anton@samba.org> > -- I'm fine with the name "powerpc". Acked-by: Steven Rostedt <rostedt@goodmis.org>
Index: linux.trees.git/arch/powerpc/include/asm/trace.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux.trees.git/arch/powerpc/include/asm/trace.h 2009-10-17 08:45:08.000000000 +1100 @@ -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 <linux/tracepoint.h> + +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 <trace/define_trace.h> Index: linux.trees.git/arch/powerpc/kernel/irq.c =================================================================== --- linux.trees.git.orig/arch/powerpc/kernel/irq.c 2009-10-17 08:44:32.000000000 +1100 +++ linux.trees.git/arch/powerpc/kernel/irq.c 2009-10-17 08:45:44.000000000 +1100 @@ -70,6 +70,8 @@ #include <asm/firmware.h> #include <asm/lv1call.h> #endif +#define CREATE_TRACE_POINTS +#include <asm/trace.h> int __irq_offset_value; static int ppc_spurious_interrupts; @@ -325,6 +327,8 @@ void do_IRQ(struct pt_regs *regs) struct pt_regs *old_regs = set_irq_regs(regs); unsigned int irq; + trace_irq_entry(regs); + irq_enter(); check_stack_overflow(); @@ -348,6 +352,8 @@ void do_IRQ(struct pt_regs *regs) timer_interrupt(regs); } #endif + + trace_irq_exit(regs); } void __init init_IRQ(void)