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Groups > linux.kernel > #1655116
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 00/10] x86: undwarf unwinder |
| Date | 2017-06-01 15:00 +0200 |
| Message-ID | <tNxRM-2EE-13@gated-at.bofh.it> (permalink) |
| References | <tNr9D-6Ua-3@gated-at.bofh.it> <tNrt0-7fK-17@gated-at.bofh.it> <tNwVI-24Q-11@gated-at.bofh.it> <tNxf3-2qB-9@gated-at.bofh.it> <tNxyr-2x0-33@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jun 01, 2017 at 02:33:20PM +0200, Jiri Slaby wrote: > On 06/01/2017, 02:17 PM, 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. 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. > > This is ~ 20 times faster than my DWARF unwinder by a quick measurement > (20000 calls to save_stack_trace via single vfs_write). Wow! Thanks for quantifying that. Looks like the lookup is indeed the bottleneck as expected. -- Josh
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[RFC PATCH 00/10] x86: undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
[RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
Re: [RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Andy Lutomirski <luto@kernel.org> - 2017-06-01 16:10 +0200
Re: [RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 16:30 +0200
Re: [RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 16:30 +0200
Re: [RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Andy Lutomirski <luto@kernel.org> - 2017-06-01 16:50 +0200
Re: [RFC PATCH 06/10] x86/entry: add CFI hint undwarf annotations Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 17:10 +0200
[RFC PATCH 09/10] extable: add undwarf table sorting ability to sorttable script Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
[RFC PATCH 08/10] extable: rename 'sortextable' script to 'sorttable' Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
[RFC PATCH 05/10] objtool, x86: add facility for asm code to provide CFI hints Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
Re: [RFC PATCH 05/10] objtool, x86: add facility for asm code to provide CFI hints Andy Lutomirski <luto@kernel.org> - 2017-06-01 16:00 +0200
Re: [RFC PATCH 05/10] objtool, x86: add facility for asm code to provide CFI hints Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 16:20 +0200
Re: [RFC PATCH 05/10] objtool, x86: add facility for asm code to provide CFI hints Andy Lutomirski <luto@kernel.org> - 2017-06-01 16:50 +0200
Re: [RFC PATCH 05/10] objtool, x86: add facility for asm code to provide CFI hints Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 17:10 +0200
[RFC PATCH 01/10] objtool: move checking code to check.c Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
[RFC PATCH 07/10] x86/asm: add CFI hint annotations to sync_core() Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
[RFC PATCH 04/10] objtool: add undwarf debuginfo generation Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
[RFC PATCH 10/10] x86/unwind: add undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 13:10 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 14:30 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Jiri Slaby <jslaby@suse.cz> - 2017-06-01 14:50 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 15:10 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 15:50 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 15:20 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 14:20 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 14:40 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 15:20 +0200
Re: [RFC PATCH 10/10] x86/unwind: add undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 17:10 +0200
[RFC PATCH 02/10] objtool, x86: add several functions and files to the objtool whitelist Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 07:50 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Ingo Molnar <mingo@kernel.org> - 2017-06-01 08:10 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 14:00 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 14:20 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Jiri Slaby <jslaby@suse.cz> - 2017-06-01 14:40 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Jiri Slaby <jslaby@suse.cz> - 2017-06-01 15:00 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 15:00 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 14:50 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Peter Zijlstra <peterz@infradead.org> - 2017-06-01 15:30 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-06-06 16:20 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Andy Lutomirski <luto@kernel.org> - 2017-06-01 16:00 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Ingo Molnar <mingo@kernel.org> - 2017-06-01 16:00 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Jiri Slaby <jslaby@suse.cz> - 2017-06-01 16:00 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Jiri Slaby <jslaby@suse.cz> - 2017-06-02 10:40 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2017-06-01 16:10 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Jiri Slaby <jslaby@suse.cz> - 2017-06-01 16:10 +0200
Re: [RFC PATCH 00/10] x86: undwarf unwinder Mel Gorman <mgorman@suse.de> - 2017-06-02 12:50 +0200
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