From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755325Ab0ASHfy (ORCPT ); Tue, 19 Jan 2010 02:35:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754968Ab0ASHfw (ORCPT ); Tue, 19 Jan 2010 02:35:52 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:49916 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755314Ab0ASHfq (ORCPT ); Tue, 19 Jan 2010 02:35:46 -0500 Message-ID: <4B55607E.8070403@cn.fujitsu.com> Date: Tue, 19 Jan 2010 15:34:22 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Steven Rostedt , linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Frederic Weisbecker Subject: [PATCH 5/6] tracing: reduce latency and remove percpu trace_seq Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __print_flags() and __print_symbolic() use percpu trace_seq: 1) Its memory is preallocated, it wastes memory when we don't use tracing. 2) It wastes memory for multi-cpus system. 3) It disables preemption when it executes its core routine "trace_seq_printf(s, "%s: ", #call);" and introduce latency for more important process. So we move this trace_seq to struct trace_iterator. Signed-off-by: Lai Jiangshan --- diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index be9ece5..348500d 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -12,9 +12,6 @@ struct dentry; #define FTRACE_SEQ_BUFSIZE PAGE_SIZE -DECLARE_PER_CPU(struct trace_seq, ftrace_event_seq); -DECLARE_PER_CPU(unsigned char[FTRACE_SEQ_BUFSIZE], ftrace_event_buffer); - struct trace_print_flags { unsigned long mask; const char *name; @@ -60,6 +57,10 @@ struct trace_iterator { struct trace_seq seq; unsigned char buffer[FTRACE_SEQ_BUFSIZE]; + /* trace_seq for __print_flags() and __print_symbolic() */ + struct trace_seq tmp_seq; + unsigned char tmp_buffer[FTRACE_SEQ_BUFSIZE]; + struct trace_entry *ent; int leftover; int cpu; diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index f30f4d6..4807d1e 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -141,8 +141,7 @@ * struct trace_seq *s = &iter->seq; * struct ftrace_raw_ *field; <-- defined in stage 1 * struct trace_entry *entry; - * struct trace_seq *p; - * unsigned char *buffer; + * struct trace_seq *p = &iter->tmp_seq; * int ret; * * entry = iter->ent; @@ -154,11 +153,8 @@ * * field = (typeof(field))entry; * - * p = get_cpu_var(ftrace_event_seq); - * buffer = get_cpu_var(ftrace_event_buffer); - * trace_seq_init(p, buffer, FTRACE_SEQ_BUFSIZE); + * trace_seq_init(p, iter->tmp_buffer, FTRACE_SEQ_BUFSIZE); * ret = trace_seq_printf(s, "\n"); - * put_cpu(); * if (!ret) * return TRACE_TYPE_PARTIAL_LINE; * @@ -208,10 +204,8 @@ ftrace_raw_output_id_##call(int event_id, const char *name, \ struct trace_seq *s = &iter->seq; \ struct ftrace_raw_##call *field; \ struct trace_entry *entry; \ - struct trace_seq *p; \ - unsigned char *buffer; \ + struct trace_seq *p = &iter->tmp_seq; \ int ret; \ - int cpu; \ \ entry = iter->ent; \ \ @@ -222,14 +216,10 @@ ftrace_raw_output_id_##call(int event_id, const char *name, \ \ field = (typeof(field))entry; \ \ - cpu = get_cpu(); \ - p = &per_cpu(ftrace_event_seq, cpu); \ - buffer = per_cpu(ftrace_event_buffer, cpu); \ - trace_seq_init(p, buffer, FTRACE_SEQ_BUFSIZE); \ + trace_seq_init(p, iter->tmp_buffer, FTRACE_SEQ_BUFSIZE); \ ret = trace_seq_printf(s, "%s: ", name); \ if (ret) \ ret = trace_seq_printf(s, print); \ - put_cpu(); \ if (!ret) \ return TRACE_TYPE_PARTIAL_LINE; \ \ @@ -253,10 +243,8 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags) \ struct trace_seq *s = &iter->seq; \ struct ftrace_raw_##template *field; \ struct trace_entry *entry; \ - struct trace_seq *p; \ - unsigned char *buffer; \ + struct trace_seq *p = &iter->tmp_seq; \ int ret; \ - int cpu; \ \ entry = iter->ent; \ \ @@ -267,14 +255,10 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags) \ \ field = (typeof(field))entry; \ \ - cpu = get_cpu(); \ - p = &per_cpu(ftrace_event_seq, cpu); \ - buffer = per_cpu(ftrace_event_buffer, cpu); \ trace_seq_init(p, buffer, FTRACE_SEQ_BUFSIZE); \ ret = trace_seq_printf(s, "%s: ", #call); \ if (ret) \ ret = trace_seq_printf(s, print); \ - put_cpu(); \ if (!ret) \ return TRACE_TYPE_PARTIAL_LINE; \ \ diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 78f9825..f531a16 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -16,11 +16,6 @@ DECLARE_RWSEM(trace_event_mutex); -DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq); -DEFINE_PER_CPU(unsigned char[PAGE_SIZE], ftrace_event_buffer); -EXPORT_PER_CPU_SYMBOL(ftrace_event_seq); -EXPORT_PER_CPU_SYMBOL(ftrace_event_buffer); - static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; static int next_event_type = __TRACE_LAST_TYPE + 1;