Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934529Ab0BYXgt (ORCPT ); Thu, 25 Feb 2010 18:36:49 -0500 Received: from va3ehsobe005.messaging.microsoft.com ([216.32.180.15]:13342 "EHLO VA3EHSOBE006.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934488Ab0BYXgs (ORCPT ); Thu, 25 Feb 2010 18:36:48 -0500 X-SpamScore: -4 X-BigFish: VPS-4(zz14c3Lab9bhzz1202hzzz2fh6bh61h) X-Spam-TCS-SCL: 0:0 Message-ID: <4B87098B.4040308@am.sony.com> Date: Thu, 25 Feb 2010 15:36:43 -0800 From: Tim Bird User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1 MIME-Version: 1.0 To: Steven Rostedt , Frederic Weisbecker , linux kernel Subject: [PATCH] ftrace: add tracing_thresh support to function_graph tracer (v3) Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Reverse-DNS: mail7.fw-bc.sony.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5052 Lines: 164 Add support for tracing_thresh to the function_graph tracer. This version of this feature isolates the checks into new entry and return functions, to avoid adding more conditional code into the main function_graph paths. Also, add support for specifying tracing_thresh on the kernel command line. When used like so: "tracing_thresh=200 ftrace=function_graph" this can be used to analyse system startup. It is important to disable tracing soon after boot, in order to avoid losing the trace data. Note: the elimination of 'notrace' in the definition of '__init' may be controversial. This can be removed, or made conditional, if it's a bit too scary, but it worked OK for me. Tracing during kernel startup still works, just with no visibility of routines declared __init. Signed-off-by: Tim Bird --- include/linux/init.h | 2 +- kernel/trace/trace.c | 20 ++++++++++++++++++-- kernel/trace/trace.h | 3 ++- kernel/trace/trace_functions_graph.c | 32 +++++++++++++++++++++++++++++--- 4 files changed, 50 insertions(+), 7 deletions(-) --- a/include/linux/init.h +++ b/include/linux/init.h @@ -40,7 +40,7 @@ /* These are for everybody (although not all archs will actually discard it in modules) */ -#define __init __section(.init.text) __cold notrace +#define __init __section(.init.text) __cold #define __initdata __section(.init.data) #define __initconst __section(.init.rodata) #define __exitdata __section(.exit.data) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -297,6 +297,21 @@ static int __init set_buf_size(char *str } __setup("trace_buf_size=", set_buf_size); +static int __init set_tracing_thresh(char *str) +{ + unsigned long threshhold; + int ret; + + if (!str) + return 0; + ret = strict_strtoul(str, 0, &threshhold); + if (ret < 0) + return 0; + tracing_thresh = threshhold * 1000; + return 1; +} +__setup("tracing_thresh=", set_tracing_thresh); + unsigned long nsecs_to_usecs(unsigned long nsecs) { return nsecs / 1000; @@ -502,9 +517,10 @@ static ssize_t trace_seq_to_buffer(struc static arch_spinlock_t ftrace_max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; +unsigned long __read_mostly tracing_thresh; + #ifdef CONFIG_TRACER_MAX_TRACE unsigned long __read_mostly tracing_max_latency; -unsigned long __read_mostly tracing_thresh; /* * Copy the new maximum trace into the separate maximum-trace @@ -4181,10 +4197,10 @@ static __init int tracer_init_debugfs(vo #ifdef CONFIG_TRACER_MAX_TRACE trace_create_file("tracing_max_latency", 0644, d_tracer, &tracing_max_latency, &tracing_max_lat_fops); +#endif trace_create_file("tracing_thresh", 0644, d_tracer, &tracing_thresh, &tracing_max_lat_fops); -#endif trace_create_file("README", 0444, d_tracer, NULL, &tracing_readme_fops); --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -396,9 +396,10 @@ extern int process_new_ksym_entry(char * extern unsigned long nsecs_to_usecs(unsigned long nsecs); +extern unsigned long tracing_thresh; + #ifdef CONFIG_TRACER_MAX_TRACE extern unsigned long tracing_max_latency; -extern unsigned long tracing_thresh; void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu); void update_max_tr_single(struct trace_array *tr, --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -241,6 +241,14 @@ int trace_graph_entry(struct ftrace_grap return ret; } +int trace_graph_thresh_entry(struct ftrace_graph_ent *trace) +{ + if (tracing_thresh) + return 1; + else + return trace_graph_entry(trace); +} + static void __trace_graph_return(struct trace_array *tr, struct ftrace_graph_ret *trace, unsigned long flags, @@ -287,13 +295,27 @@ void trace_graph_return(struct ftrace_gr local_irq_restore(flags); } +void trace_graph_thresh_return(struct ftrace_graph_ret *trace) +{ + if (tracing_thresh && + (trace->rettime - trace->calltime < tracing_thresh)) + return; + else + trace_graph_return(trace); +} + static int graph_trace_init(struct trace_array *tr) { int ret; graph_array = tr; - ret = register_ftrace_graph(&trace_graph_return, - &trace_graph_entry); + if (tracing_thresh) + ret = register_ftrace_graph(&trace_graph_thresh_return, + &trace_graph_thresh_entry); + else + ret = register_ftrace_graph(&trace_graph_return, + &trace_graph_entry); + if (ret) return ret; tracing_start_cmdline_record(); @@ -891,7 +913,11 @@ print_graph_return(struct ftrace_graph_r return TRACE_TYPE_PARTIAL_LINE; } - ret = trace_seq_printf(s, "}\n"); + if (tracing_thresh) { + ret = trace_seq_printf(s, "} (%ps)\n", (void *)trace->func); + } else { + ret = trace_seq_printf(s, "}\n"); + } if (!ret) return TRACE_TYPE_PARTIAL_LINE; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/