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From: Jeff Law <jeffreyalaw@gmail.com>
To: Hans Boehm <hboehm@google.com>, Palmer Dabbelt <palmer@rivosinc.com>
Cc: Patrick O'Neill <patrick@rivosinc.com>,
	gcc-patches@gcc.gnu.org, gnu-toolchain@rivosinc.com,
	Vineet Gupta <vineetg@rivosinc.com>,
	Andrew Waterman <andrew@sifive.com>,
	kito.cheng@sifive.com, Daniel Lustig <dlustig@nvidia.com>,
	cmuellner@gcc.gnu.org, Andrea Parri <andrea@rivosinc.com>
Subject: Re: [PATCH v5 06/11] RISC-V: Strengthen atomic stores
Date: Sun, 30 Apr 2023 11:10:12 -0600	[thread overview]
Message-ID: <81e0fa0f-2891-efab-195c-de81a714da66@gmail.com> (raw)
In-Reply-To: <CAMOCf+iF_JFx8+Gi1EKrQ6H2e64sNfm+YWYGYp6HQjBdmDMbGg@mail.gmail.com>



On 4/28/23 15:42, Hans Boehm wrote:
> The concern with making the new behavior non-default is of course that 
> the generated code will eventually end up on an A.7-capable platform.
Yea, certainly a significant concern in general, though probably not for 
Ventana.  I expect we'll have folks rebuilding as they go from V1 to V2 
due to the ventanacondops -> condops change.


> 
> An A.6-classic option for compiling code that will never run on a newer 
> machine seems OK. But I'm not sure that seq_cst stores are dynamically 
> frequent enough in C++ code for this to be worth the trouble. 
> Unlike loads, they are also costly on x86, programmers may also have 
> been somewhat trained to avoid them where possible. (And probably where 
> not possible, too :-( )
I was more worried about the kernel, perhaps because I'm less familiar 
with it these days than ever.  WRT C++, I can ping Jon@RedHat, he's got 
a great sense what's in the standard library obviously, but also a 
reasonable sense of what folks are doing in the wild.

Jeff

  parent reply	other threads:[~2023-04-30 17:10 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20220407182918.294892-1-patrick@rivosinc.com>
2023-04-05 21:01 ` [PATCH v2 0/8] RISCV: Implement ISA Manual Table A.6 Mappings Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 1/8] RISCV: Eliminate SYNC memory models Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 2/8] RISCV: Enforce Libatomic LR/SC SEQ_CST Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 3/8] RISCV: Enforce atomic compare_exchange SEQ_CST Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 4/8] RISCV: Add AMO release bits Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 5/8] RISCV: Eliminate AMO op fences Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 6/8] RISCV: Weaken compare_exchange LR/SC pairs Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 7/8] RISCV: Weaken atomic stores Patrick O'Neill
2023-04-05 21:01   ` [PATCH v2 8/8] RISCV: Weaken mem_thread_fence Patrick O'Neill
2023-04-10 18:23   ` [PATCH v3 00/10] RISCV: Implement ISA Manual Table A.6 Mappings Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 01/10] RISCV: Eliminate SYNC memory models Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 02/10] RISCV: Enforce Libatomic LR/SC SEQ_CST Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 03/10] RISCV: Enforce atomic compare_exchange SEQ_CST Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 04/10] RISCV: Add AMO release bits Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 05/10] RISCV: Strengthen atomic stores Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 06/10] RISCV: Eliminate AMO op fences Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 07/10] RISCV: Weaken compare_exchange LR/SC pairs Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 08/10] RISCV: Weaken mem_thread_fence Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 09/10] RISCV: Weaken atomic loads Patrick O'Neill
2023-04-10 18:23     ` [PATCH v3 10/10] RISCV: Table A.6 conformance tests Patrick O'Neill
2023-04-14 17:09     ` [PATCH v4 00/10] RISCV: Implement ISA Manual Table A.6 Mappings Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 01/10] RISCV: Eliminate SYNC memory models Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 02/10] RISCV: Enforce Libatomic LR/SC SEQ_CST Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 03/10] RISCV: Enforce atomic compare_exchange SEQ_CST Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 04/10] RISCV: Add AMO release bits Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 05/10] RISCV: Strengthen atomic stores Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 06/10] RISCV: Eliminate AMO op fences Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 07/10] RISCV: Weaken compare_exchange LR/SC pairs Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 08/10] RISCV: Weaken mem_thread_fence Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 09/10] RISCV: Weaken atomic loads Patrick O'Neill
2023-04-14 17:09       ` [PATCH v4 10/10] RISCV: Table A.6 conformance tests Patrick O'Neill
2023-04-27 16:22       ` [PATCH v5 00/11] RISC-V: Implement ISA Manual Table A.6 Mappings Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 01/11] RISC-V: Eliminate SYNC memory models Patrick O'Neill
2023-04-28 16:23           ` Jeff Law
2023-05-02 20:12             ` [Committed " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 02/11] RISC-V: Enforce Libatomic LR/SC SEQ_CST Patrick O'Neill
2023-04-28 16:50           ` Jeff Law
2023-05-02 20:12             ` [Committed " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 03/11] RISC-V: Enforce subword atomic " Patrick O'Neill
2023-05-02 20:14           ` [Committed " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 04/11] RISC-V: Enforce atomic compare_exchange SEQ_CST Patrick O'Neill
2023-04-28 17:23           ` Jeff Law
2023-05-02 20:15             ` [Committed " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 05/11] RISC-V: Add AMO release bits Patrick O'Neill
2023-04-28 17:34           ` Jeff Law
2023-05-02 20:16             ` Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 06/11] RISC-V: Strengthen atomic stores Patrick O'Neill
2023-04-28 17:40           ` Jeff Law
2023-04-28 17:43             ` Palmer Dabbelt
2023-04-28 21:42               ` Hans Boehm
2023-04-28 22:21                 ` Hans Boehm
2023-04-30 17:10                 ` Jeff Law [this message]
2023-05-02 20:18             ` [Committed " Patrick O'Neill
2023-05-02 16:11           ` [PATCH v5 " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 07/11] RISC-V: Eliminate AMO op fences Patrick O'Neill
2023-04-28 17:43           ` Jeff Law
2023-05-02 20:19             ` [Committed " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 08/11] RISC-V: Weaken LR/SC pairs Patrick O'Neill
2023-04-28 17:56           ` Jeff Law
2023-05-02 20:19             ` [Committed " Patrick O'Neill
2023-04-27 16:22         ` [PATCH v5 09/11] RISC-V: Weaken mem_thread_fence Patrick O'Neill
2023-04-28 18:00           ` Jeff Law
2023-05-02 20:20             ` [Committed " Patrick O'Neill
2023-05-03 12:18           ` [PATCH v5 " Andreas Schwab
2023-05-03 12:22             ` Martin Liška
2023-04-27 16:23         ` [PATCH v5 10/11] RISC-V: Weaken atomic loads Patrick O'Neill
2023-04-28 18:04           ` Jeff Law
2023-05-02 20:20             ` [Committed " Patrick O'Neill
2023-04-27 16:23         ` [PATCH v5 11/11] RISC-V: Table A.6 conformance tests Patrick O'Neill
2023-04-28 18:07           ` Jeff Law
2023-05-02 20:28             ` [Committed " Patrick O'Neill
2023-04-27 17:20         ` [PATCH v5 00/11] RISC-V: Implement ISA Manual Table A.6 Mappings Andrea Parri
2023-04-28 16:14         ` Jeff Law
2023-04-28 16:29           ` Palmer Dabbelt
2023-04-28 17:44             ` Patrick O'Neill
2023-04-28 18:18               ` Patrick O'Neill
     [not found]               ` <CAMOCf+hK9nedV+UeENbTn=Uy3RpYLeMt04mLiLmDsZyNm83CCg@mail.gmail.com>
2023-04-30 16:37                 ` Jeff Law
2023-07-25 18:01         ` [gcc13 backport 00/12] " Patrick O'Neill
2023-07-25 18:01           ` [gcc13 backport 01/12] RISC-V: Eliminate SYNC memory models Patrick O'Neill
2023-07-25 18:01           ` [gcc13 backport 02/12] RISC-V: Enforce Libatomic LR/SC SEQ_CST Patrick O'Neill
2023-07-25 18:01           ` [gcc13 backport 03/12] RISC-V: Enforce subword atomic " Patrick O'Neill
2023-07-25 18:01           ` [gcc13 backport 04/12] RISC-V: Enforce atomic compare_exchange SEQ_CST Patrick O'Neill
2023-07-25 18:01           ` [gcc13 backport 05/12] RISC-V: Add AMO release bits Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 06/12] RISC-V: Strengthen atomic stores Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 07/12] RISC-V: Eliminate AMO op fences Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 08/12] RISC-V: Weaken LR/SC pairs Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 09/12] RISC-V: Weaken mem_thread_fence Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 10/12] RISC-V: Weaken atomic loads Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 11/12] RISC-V: Table A.6 conformance tests Patrick O'Neill
2023-07-25 18:02           ` [gcc13 backport 12/12] riscv: fix error: control reaches end of non-void function Patrick O'Neill
2023-07-26  1:22             ` Kito Cheng
2023-07-26 17:41               ` Patrick O'Neill
2023-07-25 19:50           ` [gcc13 backport 00/12] RISC-V: Implement ISA Manual Table A.6 Mappings Jakub Jelinek
2023-07-25 20:01             ` Palmer Dabbelt
2023-07-25 21:02             ` Jeff Law
2023-07-25 21:16               ` Palmer Dabbelt
2023-07-25 19:58           ` Palmer Dabbelt
2023-07-31 16:19           ` [Committed] " Patrick O'Neill

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