From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753039Ab3FQUWj (ORCPT ); Mon, 17 Jun 2013 16:22:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:16994 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751320Ab3FQUWi (ORCPT ); Mon, 17 Jun 2013 16:22:38 -0400 Date: Mon, 17 Jun 2013 22:18:18 +0200 From: Oleg Nesterov To: Masami Hiramatsu , Steven Rostedt Cc: Frederic Weisbecker , Ingo Molnar , Srikar Dronamraju , "zhangwei(Jovi)" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] tracing: more list_empty(perf_events) checks Message-ID: <20130617201818.GA12349@redhat.com> References: <20130617170142.GA19780@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130617170142.GA19780@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/17, Oleg Nesterov wrote: > > DECLARE_EVENT_CLASS()->perf_trace_##call() is not trivial because > of __perf_task() Perhaps we can do something like below? Then we can 1. kill __perf_addr(), __perf_count(), __perf_task() and TP_perf_assign() 2. Add the fast path check if (builtin_constant(__task) && !__task && hlist_empty(head))) return; into perf_trace_call() right after ftrace_get_offsets_call(). Doesn't look very nice, it relies on the fact that ftrace_get_offsets_call(args) evaluates TP_perf_arg()'s hidden in TP_ARGS(). OTOH, the whole point of include/trace/ is to create the code which nobody except the maintainers can understand. At least I certainly can't ;) So perhaps this is fine. Oleg. --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -57,7 +57,7 @@ DECLARE_EVENT_CLASS(sched_wakeup_template, TP_PROTO(struct task_struct *p, int success), - TP_ARGS(p, success), + TP_ARGS(TP_perf_arg(__task, p), success), TP_STRUCT__entry( __array( char, comm, TASK_COMM_LEN ) @@ -73,9 +73,6 @@ DECLARE_EVENT_CLASS(sched_wakeup_template, __entry->prio = p->prio; __entry->success = success; __entry->target_cpu = task_cpu(p); - ) - TP_perf_assign( - __perf_task(p); ), TP_printk("comm=%s pid=%d prio=%d success=%d target_cpu=%03d", @@ -313,7 +310,7 @@ DECLARE_EVENT_CLASS(sched_stat_template, TP_PROTO(struct task_struct *tsk, u64 delay), - TP_ARGS(tsk, delay), + TP_ARGS(TP_perf_arg(__task, tsk), TP_perf_arg(__count, delay)), TP_STRUCT__entry( __array( char, comm, TASK_COMM_LEN ) @@ -325,10 +322,6 @@ DECLARE_EVENT_CLASS(sched_stat_template, memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN); __entry->pid = tsk->pid; __entry->delay = delay; - ) - TP_perf_assign( - __perf_count(delay); - __perf_task(tsk); ), TP_printk("comm=%s pid=%d delay=%Lu [ns]", --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -506,6 +506,9 @@ static inline notrace int ftrace_get_offsets_##call( \ #undef TP_perf_assign #define TP_perf_assign(args...) +#undef TP_perf_arg +#define TP_perf_arg(var, val) (val) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ \ @@ -643,6 +646,9 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call #undef TP_perf_assign #define TP_perf_assign(args...) args +#undef TP_perf_arg +#define TP_perf_arg(var, val) (var = (val)) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ static notrace void \ @@ -659,13 +665,12 @@ perf_trace_##call(void *__data, proto) \ int __data_size; \ int rctx; \ \ - perf_fetch_caller_regs(&__regs); \ - \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\ sizeof(u64)); \ __entry_size -= sizeof(u32); \ \ + perf_fetch_caller_regs(&__regs); \ entry = (struct ftrace_raw_##call *)perf_trace_buf_prepare( \ __entry_size, event_call->event.type, &__regs, &rctx); \ if (!entry) \