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From: "Andi Kleen" <andi@firstfloor.org>
To: "Steven Rostedt" <rostedt@goodmis.org>
Cc: "Andi Kleen" <andi@firstfloor.org>,
	"Jason Baron" <jbaron@redhat.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu,
	mathieu.desnoyers@polymtl.ca, hpa@zytor.com, tglx@linutronix.de,
	roland@redhat.com, rth@redhat.com, mhiramat@redhat.com,
	fweisbec@gmail.com, avi@redhat.com, davem@davemloft.net,
	vgoyal@redhat.com, sam@ravnborg.org, tony@bakeyournoodle.com
Subject: Re: [PATCH 03/10] jump label v11: base patch
Date: Tue, 21 Sep 2010 19:39:04 +0200	[thread overview]
Message-ID: <04c02fdea99c71ad5f166152c9331f2d.squirrel@www.firstfloor.org> (raw)
In-Reply-To: <1285082049.23122.1930.camel@gandalf.stny.rr.com>


>> Even 1000 is fine to walk, but if it was sorted a binary search
>> would be much faster anyways. That is then you would still
>> need to search for each module, but that is a relatively small
>> number (< 100)
>
> xfs has > 100 tracepoints

No problem for binary search.

>> > Also, I think the hash table deals nicely with modules.
>>
>> Maybe but it's also a lot of code. And it seems to me
>> that it is optimizing the wrong thing. Simpler is nicer.
>
> I guess simplicity is in the eye of the beholder. I find hashes easier
> to deal with than binary searching sorted lists. Every time you add a
> tracepoint, you need to resort the list.

You only add trace points with new modules right?
In this case you only sort the section of the new module, nothing else.
And only once when you load it.

> Hashes are much easier to deal with and scale nicely. I don't think
> there's enough rational to switch this to a binary list.

The problem I see is that there's a lot of hashing related code
and a lot of memory overhead. I suspect with inplace access
everything would be much simpler and less overhead.

For me the current implementation simply seems overengineered.

-Andi


  parent reply	other threads:[~2010-09-21 17:39 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-17 15:08 [PATCH 00/10] jump label v11 Jason Baron
2010-09-17 15:08 ` [PATCH 01/10] jump label v11: make dynamic no-op selection available outside of ftrace Jason Baron
2010-09-17 15:28   ` Steven Rostedt
2010-09-24  8:58   ` [tip:perf/core] jump label: Make " tip-bot for Jason Baron
2010-09-17 15:08 ` [PATCH 02/10] jump label v11: make text_poke_early() globally visisble Jason Baron
2010-09-24  8:58   ` [tip:perf/core] jump label: Make text_poke_early() globally visible tip-bot for Jason Baron
2010-09-17 15:09 ` [PATCH 03/10] jump label v11: base patch Jason Baron
2010-09-17 18:21   ` David Miller
2010-09-21  2:37   ` Steven Rostedt
2010-09-21 13:12   ` Andi Kleen
2010-09-21 14:35     ` Jason Baron
2010-09-21 14:41       ` Andi Kleen
2010-09-21 15:04         ` Jason Baron
2010-09-21 15:09         ` Ingo Molnar
2010-09-21 15:14         ` Steven Rostedt
2010-09-21 17:35           ` H. Peter Anvin
2010-09-21 17:42             ` Andi Kleen
2010-09-21 17:36           ` Andi Kleen
2010-09-21 18:05             ` Steven Rostedt
2010-09-21 18:24               ` Mathieu Desnoyers
2010-09-21 19:48                 ` Andi Kleen
2010-09-21 18:48               ` Andi Kleen
2010-09-21 17:39           ` Andi Kleen [this message]
2010-09-21 18:29   ` Konrad Rzeszutek Wilk
2010-09-21 18:55     ` Konrad Rzeszutek Wilk
2010-09-21 18:58       ` H. Peter Anvin
2010-09-24  8:59   ` [tip:perf/core] jump label: Base patch for jump label tip-bot for Jason Baron
2010-09-17 15:09 ` [PATCH 04/10] jump label v11: initialize workqueue tracepoints *before* they are registered Jason Baron
2010-09-24  8:59   ` [tip:perf/core] jump label: Initialize " tip-bot for Jason Baron
2010-09-17 15:09 ` [PATCH 05/10] jump label v11: jump_label_text_reserved() to reserve our jump points Jason Baron
2010-09-24  9:00   ` [tip:perf/core] jump label: Add jump_label_text_reserved() to reserve " tip-bot for Jason Baron
2010-09-17 15:09 ` [PATCH 06/10] jump label v11: tracepoint support Jason Baron
2010-09-24  9:00   ` [tip:perf/core] jump label: Tracepoint support for jump labels tip-bot for Jason Baron
2010-09-17 15:09 ` [PATCH 07/10] jump label v11: convert dynamic debug to use " Jason Baron
2010-09-24  9:00   ` [tip:perf/core] jump label: Convert " tip-bot for Jason Baron
2010-09-17 15:09 ` [PATCH 08/10] jump label v11: x86 support Jason Baron
2010-09-21  2:32   ` Steven Rostedt
2010-09-21  2:43   ` H. Peter Anvin
2010-09-21 15:25     ` Jason Baron
2010-09-21 15:29       ` Ingo Molnar
2010-09-21 15:35         ` Steven Rostedt
2010-09-21 16:33           ` Jason Baron
2010-09-21 18:30   ` Konrad Rzeszutek Wilk
2010-09-24  9:01   ` [tip:perf/core] jump label: " tip-bot for Jason Baron
2010-09-24 16:19     ` H. Peter Anvin
2010-09-24 16:34       ` Jason Baron
2010-09-24 17:30         ` H. Peter Anvin
2010-09-24 18:08           ` Steven Rostedt
2010-10-18 11:17     ` Peter Zijlstra
2010-10-18 12:48       ` Mathieu Desnoyers
2010-09-17 15:09 ` [PATCH 09/10] jump label 11: add sparc64 support Jason Baron
2010-09-20 22:25   ` Steven Rostedt
2010-09-20 22:30     ` David Miller
2010-09-20 22:38       ` Steven Rostedt
2010-09-21 15:37   ` Steven Rostedt
2010-09-21 16:27     ` David Miller
2010-09-23  3:09       ` Steven Rostedt
2010-09-24  9:01   ` [tip:perf/core] jump label: Add " tip-bot for David S. Miller
2010-09-17 15:09 ` [PATCH 10/10] jump label v11: add docs Jason Baron
2010-09-17 16:05   ` Mathieu Desnoyers
2010-09-20 22:28     ` Steven Rostedt
2010-09-21 16:20       ` Jason Baron
2010-09-21  8:20   ` matt mooney
2010-09-21 18:39   ` Konrad Rzeszutek Wilk

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