From: Thomas Neumann <thomas.neumann@in.tum.de>
To: Florian Weimer <fweimer@redhat.com>
Cc: "H.J. Lu" <hjl.tools@gmail.com>, Jakub Jelinek <jakub@redhat.com>,
Tamar Christina <Tamar.Christina@arm.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
Jason Merrill <jason@redhat.com>,
Jonathan Wakely <jwakely.gcc@gmail.com>
Subject: Re: [PATCH v4] eliminate mutex in fast path of __register_frame
Date: Tue, 22 Nov 2022 10:12:07 +0100 [thread overview]
Message-ID: <95d6d5eb-2dcc-e085-965c-d4cba1fa1cf6@in.tum.de> (raw)
In-Reply-To: <87sfibqu1s.fsf@oldenburg.str.redhat.com>
> Would it be possible to trigger lazy registration if the version is read
> as a zero? This would not introduce any additional atomic instructions
> on the fast path.
yes, that is possible. The main problem is the transition from lazy to
non-lazy mode when the first exception is thrown. We must somehow stop
the world for that without introducing an additional mutex. But I have
though about that some more, and that is possible too, by encoding a
magic value as version during the transition, which causes the other
threads to block. A bit ugly, but manageable. I will implement that in a
few days.
Independent of that I think we should improve the sort logic, as we
still have to sort, even in lazy mode, at latest when the first
exception is thrown. I have send a patch that significantly improves
that step.
Best
Thomas
next prev parent reply other threads:[~2022-11-22 9:12 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 10:19 Thomas Neumann
2022-09-16 14:49 ` Jason Merrill
2022-09-18 8:59 ` Dimitar Dimitrov
2022-09-18 9:20 ` Thomas Neumann
2022-09-18 10:02 ` Thomas Neumann
2022-09-19 13:46 ` Stephan Bergmann
2022-09-19 13:55 ` Thomas Neumann
2022-09-19 14:00 ` Stephan Bergmann
2022-09-19 15:33 ` Thomas Neumann
2022-09-20 5:39 ` Stephan Bergmann
2022-11-21 11:14 ` Tamar Christina
2022-11-21 11:22 ` Thomas Neumann
2022-11-21 11:48 ` Jakub Jelinek
2022-11-21 17:13 ` H.J. Lu
2022-11-22 0:31 ` Thomas Neumann
2022-11-22 8:20 ` Florian Weimer
2022-11-22 9:12 ` Thomas Neumann [this message]
2022-12-09 17:34 ` [PATCH] initialize fde objects lazily Thomas Neumann
2022-12-15 16:11 ` Tamar Christina
2022-12-16 17:25 ` Jason Merrill
2023-05-02 14:32 ` [PATCH] release the sorted FDE array when deregistering a frame [PR109685] Thomas Neumann
2023-05-10 10:49 ` [PATCH] fix radix sort on 32bit platforms [PR109670] Thomas Neumann
2023-08-10 11:33 ` [PATCH] preserve base pointer for __deregister_frame [PR110956] Thomas Neumann
2023-08-11 15:21 ` Jeff Law
2024-03-15 10:29 ` [PATCH] handle unwind tables that are embedded within unwinding code, [PR111731] Thomas Neumann
2024-03-20 8:25 ` Richard Biener
2024-03-22 13:35 ` Jeff Law
2024-03-22 13:36 ` Jeff Law
2024-03-22 14:43 ` Thomas Neumann
2022-11-22 8:00 ` [PATCH] speed up end_fde_sort using radix sort Thomas Neumann
2022-12-16 18:02 ` Jason Merrill
2022-11-21 11:49 ` [PATCH v4] eliminate mutex in fast path of __register_frame Tamar Christina
2022-11-21 11:53 ` Thomas Neumann
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