From patchwork Tue Oct 6 02:19:03 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 35059 X-Patchwork-Delegate: benh@kernel.crashing.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from bilbo.ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id 42DCBB7C7D for ; Tue, 6 Oct 2009 13:19:11 +1100 (EST) Received: by ozlabs.org (Postfix, from userid 1010) id 364DBB7BA8; Tue, 6 Oct 2009 13:19:05 +1100 (EST) Date: Tue, 6 Oct 2009 13:19:03 +1100 From: Anton Blanchard To: Steven Rostedt , Frederic Weisbecker , Ingo Molnar , benh@kernel.crashing.org Subject: [PATCH] powerpc: tracing: Add powerpc tracepoints for interrupt entry and exit Message-ID: <20091006021903.GC16073@kryten> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Cc: linuxppc-dev@lists.ozlabs.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org 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: -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. 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 Index: linux.trees.git/arch/powerpc/kernel/irq.c =================================================================== --- linux.trees.git.orig/arch/powerpc/kernel/irq.c 2009-10-06 11:11:44.000000000 +1100 +++ linux.trees.git/arch/powerpc/kernel/irq.c 2009-10-06 11:15:09.000000000 +1100 @@ -54,6 +54,8 @@ #include #include #include +#define CREATE_TRACE_POINTS +#include #include #include @@ -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) Index: linux.trees.git/include/trace/events/powerpc.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux.trees.git/include/trace/events/powerpc.h 2009-10-06 11:14:05.000000000 +1100 @@ -0,0 +1,47 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM powerpc + +#if !defined(_TRACE_POWERPC_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_POWERPC_H + +#include +#include + +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 */ + +/* This part must be outside protection */ +#include