From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
live-patching@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>, Jiri Slaby <jslaby@suse.cz>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [RFC PATCH 00/10] x86: undwarf unwinder
Date: Thu, 1 Jun 2017 07:47:05 -0500 [thread overview]
Message-ID: <20170601124705.gw5snmcsetsrhw24@treble> (raw)
In-Reply-To: <20170601121721.lezoecnyah3aic6a@hirez.programming.kicks-ass.net>
On Thu, Jun 01, 2017 at 02:17:21PM +0200, Peter Zijlstra wrote:
> On Thu, Jun 01, 2017 at 06:58:20AM -0500, Josh Poimboeuf wrote:
> > > Being able to generate more optimal code in the hottest code paths of the kernel
> > > is the _real_, primary upstream kernel benefit of a different debuginfo method -
> > > which has to be weighed against the pain of introducing a new unwinder. But this
> > > submission does not talk about that aspect at all, which should be fixed I think.
> >
> > Actually I devoted an entire one-sentence paragraph to performance in
> > the documentation:
> >
> > The simpler debuginfo format also enables the unwinder to be relatively
> > fast, which is important for perf and lockdep.
> >
> > But I'll try to highlight that a little more.
>
> That's relative to a DWARF unwinder.
Yes.
> It doesn't appear to be possible to get anywhere near a frame-pointer
> unwinder due to having to do this log(n) lookup for every single
> frame.
Hm, is there something faster, yet not substantially bigger? Hash?
Trie?
--
Josh
next prev parent reply other threads:[~2017-06-01 12:47 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-01 5:44 [RFC PATCH 00/10] x86: undwarf unwinder Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 01/10] objtool: move checking code to check.c Josh Poimboeuf
2017-06-14 7:22 ` Jiri Slaby
2017-06-01 5:44 ` [RFC PATCH 02/10] objtool, x86: add several functions and files to the objtool whitelist Josh Poimboeuf
2017-06-14 7:24 ` Jiri Slaby
2017-06-14 13:03 ` Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 03/10] objtool: stack validation 2.0 Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 04/10] objtool: add undwarf debuginfo generation Josh Poimboeuf
2017-06-14 8:42 ` Jiri Slaby
2017-06-14 13:27 ` Josh Poimboeuf
2017-06-22 7:47 ` Jiri Slaby
2017-06-22 12:49 ` Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 05/10] objtool, x86: add facility for asm code to provide CFI hints Josh Poimboeuf
2017-06-01 13:57 ` Andy Lutomirski
2017-06-01 14:16 ` Josh Poimboeuf
2017-06-01 14:40 ` Andy Lutomirski
2017-06-01 15:02 ` Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Josh Poimboeuf
2017-06-01 14:03 ` Andy Lutomirski
2017-06-01 14:23 ` Josh Poimboeuf
2017-06-01 14:28 ` Josh Poimboeuf
2017-06-01 14:39 ` Andy Lutomirski
2017-06-01 15:01 ` Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 07/10] x86/asm: add CFI hint annotations to sync_core() Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 08/10] extable: rename 'sortextable' script to 'sorttable' Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 09/10] extable: add undwarf table sorting ability to sorttable script Josh Poimboeuf
2017-06-01 5:44 ` [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Josh Poimboeuf
2017-06-01 11:05 ` Peter Zijlstra
2017-06-01 12:26 ` Josh Poimboeuf
2017-06-01 12:47 ` Jiri Slaby
2017-06-01 13:02 ` Josh Poimboeuf
2017-06-01 13:42 ` Peter Zijlstra
2017-06-01 13:10 ` Peter Zijlstra
2017-06-01 12:13 ` Peter Zijlstra
2017-06-01 12:36 ` Josh Poimboeuf
2017-06-01 13:12 ` Peter Zijlstra
2017-06-01 15:03 ` Josh Poimboeuf
2017-06-14 11:45 ` Jiri Slaby
2017-06-14 13:44 ` Josh Poimboeuf
2017-06-01 6:08 ` [RFC PATCH 00/10] x86: " Ingo Molnar
2017-06-01 11:58 ` Josh Poimboeuf
2017-06-01 12:17 ` Peter Zijlstra
2017-06-01 12:33 ` Jiri Slaby
2017-06-01 12:52 ` Josh Poimboeuf
2017-06-01 12:57 ` Jiri Slaby
2017-06-01 12:47 ` Josh Poimboeuf [this message]
2017-06-01 13:25 ` Peter Zijlstra
2017-06-06 14:14 ` Sergey Senozhatsky
2017-06-01 13:50 ` Andy Lutomirski
2017-06-01 13:50 ` Ingo Molnar
2017-06-01 13:58 ` Jiri Slaby
2017-06-02 8:30 ` Jiri Slaby
2017-06-01 14:05 ` Josh Poimboeuf
2017-06-01 14:08 ` Jiri Slaby
2017-06-02 10:40 ` Mel Gorman
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