From: Andi Kleen <andi@firstfloor.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.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: Re: [PATCH -tip v7 24/26] kprobes: Enlarge hash table to 4096 entries
Date: Thu, 27 Feb 2014 21:46:00 -0000 [thread overview]
Message-ID: <87y50wut4j.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <20140227073414.20992.16882.stgit@ltc230.yrl.intra.hitachi.co.jp> (Masami Hiramatsu's message of "Thu, 27 Feb 2014 16:34:14 +0900")
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> writes:
> Currently, since the kprobes expects to be used
> with less than 100 probe points, its hash table
> just has 64 entries. This is too little to handle
> several thousands of probes.
> Enlarge this to 4096 entires which just consumes
> 32KB (on 64bit arch) for better scalability.
32K for a debug feature that most systems never use seems
too large to me.
First can you check if smaller hash tables work too
(perhaps with a better hash, like jhash)
And then if you enlarge the table please allocate
it dynamically on the first use.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2014-02-27 21:46 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 7:33 [PATCH -tip v7 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 12/26] ftrace/*probes: Allow probing on some functions Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 01/26] [BUGFIX]kprobes/x86: Fix page-fault handling logic Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 10/26] kprobes/x86: Allow probe on some kprobe preparation functions Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 03/26] kprobes: Prohibit probing on .entry.text code Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 06/26] [BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 09/26] x86: Call exception_enter after kprobes handled Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 11/26] kprobes: Allow probe on some kprobe functions Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 13/26] x86: Allow kprobes on text_poke/hw_breakpoint Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 04/26] kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 08/26] kprobes/x86: Call exception handlers directly from do_int3/do_debug Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 15/26] kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 02/26] kprobes/x86: Allow to handle reentered kprobe on singlestepping Masami Hiramatsu
2014-02-27 7:33 ` [PATCH -tip v7 05/26] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 25/26] kprobes: Introduce kprobe cache to reduce cache misshits Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 20/26] kprobes: Support blacklist functions in module Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 24/26] kprobes: Enlarge hash table to 4096 entries Masami Hiramatsu
2014-02-27 21:46 ` Andi Kleen [this message]
2014-02-27 22:22 ` Masami Hiramatsu
2014-03-03 9:31 ` Masami Hiramatsu
2014-03-03 17:20 ` Andi Kleen
2014-03-04 1:54 ` Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 17/26] notifier: Use NOKPROBE_SYMBOL macro in notifier Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 19/26] kprobes: Show blacklist entries via debugfs Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 16/26] ftrace/kprobes: Use NOKPROBE_SYMBOL macro in ftrace Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 18/26] sched: Use NOKPROBE_SYMBOL macro in sched Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 21/26] kprobes: Use NOKPROBE_SYMBOL() in sample modules Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 23/26] kprobes/x86: Remove unneeded preempt_disable/enable in interrupt handlers Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 14/26] x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 26/26] ftrace: Introduce FTRACE_OPS_FL_SELF_FILTER for ftrace-kprobe Masami Hiramatsu
2014-02-27 7:34 ` [PATCH -tip v7 22/26] kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text Masami Hiramatsu
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