From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Sandeepa Prabhu <sandeepa.prabhu@linaro.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
x86@kernel.org, Steven Rostedt <rostedt@goodmis.org>,
fche@redhat.com, mingo@redhat.com, systemtap@sourceware.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH -tip v9 26/26] ftrace: Introduce FTRACE_OPS_FL_SELF_FILTER for ftrace-kprobe
Date: Thu, 17 Apr 2014 17:19:38 +0900 [thread overview]
Message-ID: <20140417081937.26341.73274.stgit@ltc230.yrl.intra.hitachi.co.jp> (raw)
In-Reply-To: <20140417081636.26341.87858.stgit@ltc230.yrl.intra.hitachi.co.jp>
Since the kprobes itself owns a hash table to get a kprobe
data structure corresponding to the given ip address, there
is no need to test ftrace hash in ftrace side.
To achive better performance on ftrace-based kprobe,
FTRACE_OPS_FL_SELF_FILTER flag to ftrace_ops which means
that ftrace skips testing its own hash table.
Without this patch, ftrace_lookup_ip() is biggest cycles
consumer when 20,000 kprobes are enabled.
----
Samples: 1K of event 'cycles', Event count (approx.): 340068894
+ 20.77% [k] ftrace_lookup_ip
+ 8.33% [k] kprobe_trace_func
+ 4.83% [k] get_kprobe_cached
----
With this patch, ftrace_lookup_ip() vanished from the
cycles consumer list (of course, there is no caller on
hotpath anymore :))
----
Samples: 1K of event 'cycles', Event count (approx.): 186861492
+ 9.95% [k] kprobe_trace_func
+ 6.00% [k] kprobe_ftrace_handler
+ 5.53% [k] get_kprobe_cached
----
Changes from v7:
- Re-evaluate the performance improvement.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
---
include/linux/ftrace.h | 3 +++
kernel/kprobes.c | 2 +-
kernel/trace/ftrace.c | 3 ++-
3 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 9212b01..36e4cb5 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -93,6 +93,8 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
* INITIALIZED - The ftrace_ops has already been initialized (first use time
* register_ftrace_function() is called, it will initialized the ops)
* DELETED - The ops are being deleted, do not let them be registered again.
+ * SELF_FILTER - The ftrace_ops function filters ip by itself. Do not need to
+ * check hash table on each hit.
*/
enum {
FTRACE_OPS_FL_ENABLED = 1 << 0,
@@ -105,6 +107,7 @@ enum {
FTRACE_OPS_FL_STUB = 1 << 7,
FTRACE_OPS_FL_INITIALIZED = 1 << 8,
FTRACE_OPS_FL_DELETED = 1 << 9,
+ FTRACE_OPS_FL_SELF_FILTER = 1 << 10,
};
/*
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 465e912..af1ff6a 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1020,7 +1020,7 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
#ifdef CONFIG_KPROBES_ON_FTRACE
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
.func = kprobe_ftrace_handler,
- .flags = FTRACE_OPS_FL_SAVE_REGS,
+ .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_SELF_FILTER,
};
static int kprobe_ftrace_enabled;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1fd4b94..4235851 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4520,7 +4520,8 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (ftrace_ops_test(op, ip, regs))
+ if (op->flags & FTRACE_OPS_FL_SELF_FILTER ||
+ ftrace_ops_test(op, ip, regs))
op->func(ip, parent_ip, op, regs);
} while_for_each_ftrace_op(op);
preempt_enable_notrace();
next prev parent reply other threads:[~2014-04-17 8:19 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-17 8:16 [PATCH -tip v9 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 01/26] [BUGFIX]kprobes/x86: Fix page-fault handling logic Masami Hiramatsu
2014-04-17 9:58 ` [tip:perf/urgent] kprobes/x86: " tip-bot for Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 02/26] kprobes/x86: Allow to handle reentered kprobe on singlestepping Masami Hiramatsu
2014-04-24 10:57 ` [tip:perf/kprobes] kprobes/x86: Allow to handle reentered kprobe on single-stepping tip-bot for Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 03/26] kprobes: Prohibit probing on .entry.text code Masami Hiramatsu
2014-04-24 10:57 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 04/26] kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist tip-bot for Masami Hiramatsu
2014-05-01 5:26 ` kprobes broken in linux-next (was Re: [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist) Vineet Gupta
2014-05-02 1:13 ` Masami Hiramatsu
2014-05-07 4:56 ` Vineet Gupta
2014-05-07 19:18 ` [tip:perf/kprobes] kprobes: Ensure blacklist data is aligned tip-bot for Vineet Gupta
2014-05-05 20:48 ` [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist Tony Luck
2014-05-06 9:25 ` Masami Hiramatsu
2014-05-06 10:03 ` Masami Hiramatsu
2014-05-07 11:19 ` Masami Hiramatsu
2014-05-07 11:55 ` [RFT PATCH -next ] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64 Masami Hiramatsu
2014-05-07 11:59 ` Masami Hiramatsu
2014-05-14 8:19 ` Masami Hiramatsu
2014-05-08 4:47 ` Ananth N Mavinakayanahalli
2014-05-08 5:40 ` Masami Hiramatsu
2014-05-08 6:16 ` Ananth N Mavinakayanahalli
2014-05-09 8:06 ` Masami Hiramatsu
2014-05-26 11:25 ` Suzuki K. Poulose
2014-05-26 11:48 ` Masami Hiramatsu
2014-05-27 6:31 ` [RFT PATCH -next v2] " Masami Hiramatsu
2014-05-29 19:13 ` Suzuki K. Poulose
2014-05-30 2:47 ` Masami Hiramatsu
2014-05-30 3:18 ` [RFT PATCH -next v3] " Masami Hiramatsu
2014-06-06 6:38 ` Masami Hiramatsu
2014-06-17 23:03 ` Tony Luck
2014-06-18 7:56 ` Michael Ellerman
2014-06-18 8:46 ` Masami Hiramatsu
2014-06-19 1:30 ` Michael Ellerman
2014-06-19 4:52 ` Masami Hiramatsu
2014-06-19 6:40 ` Suzuki K. Poulose
2014-06-19 7:26 ` Masami Hiramatsu
2014-06-19 9:45 ` Suzuki K. Poulose
2014-06-19 11:01 ` Masami Hiramatsu
2014-06-19 11:20 ` Masami Hiramatsu
2014-06-20 0:37 ` Michael Ellerman
2014-06-20 2:13 ` Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 05/26] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, x86: Prohibit probing on debug_stack_*() tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 06/26] [BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, x86: Prohibit probing on native_set_debugreg()/load_idt() tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 08/26] kprobes/x86: Call exception handlers directly from do_int3/do_debug Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-24 11:26 ` Jiri Kosina
2014-04-17 8:17 ` [PATCH -tip v9 09/26] x86: Call exception_enter after kprobes handled Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-06-13 17:14 ` Frederic Weisbecker
2014-06-14 5:44 ` Masami Hiramatsu
2014-06-14 6:47 ` [PATCH -tip ] [Bugfix] x86/kprobes: Fix build errors and blacklist context_track_user Masami Hiramatsu
2014-06-14 8:58 ` [tip:perf/urgent] " tip-bot for Masami Hiramatsu
2014-06-16 15:52 ` [PATCH -tip ] [Bugfix] " Frederic Weisbecker
2014-04-17 8:17 ` [PATCH -tip v9 10/26] kprobes/x86: Allow probe on some kprobe preparation functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 11/26] kprobes: Allow probe on some kprobe functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 12/26] ftrace/*probes: Allow probing on some functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] kprobes, ftrace: " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 13/26] x86: Allow kprobes on text_poke/hw_breakpoint Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, x86: Allow kprobes on text_poke/ hw_breakpoint tip-bot for Masami Hiramatsu
2014-04-24 11:26 ` Jiri Kosina
2014-04-17 8:18 ` [PATCH -tip v9 14/26] x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 15/26] kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 16/26] ftrace/kprobes: Use NOKPROBE_SYMBOL macro in ftrace Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, ftrace: " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 17/26] notifier: Use NOKPROBE_SYMBOL macro in notifier Masami Hiramatsu
2014-04-17 14:40 ` Josh Triplett
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 18/26] sched: Use NOKPROBE_SYMBOL macro in sched Masami Hiramatsu
2014-04-24 11:01 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 19/26] kprobes: Show blacklist entries via debugfs Masami Hiramatsu
2014-04-24 11:01 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 20/26] kprobes: Support blacklist functions in module Masami Hiramatsu
2014-04-24 8:56 ` Ingo Molnar
2014-04-24 11:24 ` Masami Hiramatsu
2014-04-25 8:19 ` Ingo Molnar
2014-04-25 10:12 ` Masami Hiramatsu
2014-04-25 10:55 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 21/26] kprobes: Use NOKPROBE_SYMBOL() in sample modules Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 22/26] kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text Masami Hiramatsu
2014-04-24 8:58 ` Ingo Molnar
2014-04-24 11:22 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 23/26] kprobes/x86: Remove unneeded preempt_disable/enable in interrupt handlers Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 24/26] kprobes: Enlarge hash table to 512 entries Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 25/26] kprobes: Introduce kprobe cache to reduce cache misshits Masami Hiramatsu
2014-04-24 9:01 ` Ingo Molnar
2014-04-24 11:38 ` Masami Hiramatsu
2014-04-25 8:20 ` Ingo Molnar
2014-04-25 9:43 ` Masami Hiramatsu
2014-04-26 7:12 ` Ingo Molnar
2014-04-27 12:49 ` Masami Hiramatsu
2014-04-17 8:19 ` Masami Hiramatsu [this message]
2014-04-17 8:37 ` [PATCH -tip v9 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Ingo Molnar
2014-04-17 8:53 ` Masami Hiramatsu
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