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From: Richard Henderson <richard.henderson@linaro.org>
To: Paolo Savini <paolo.savini@embecosm.com>,
	qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Alistair Francis <alistair.francis@wdc.com>,
	Bin Meng <bmeng.cn@gmail.com>, Weiwei Li <liwei1518@gmail.com>,
	Daniel Henrique Barboza <dbarboza@ventanamicro.com>,
	Liu Zhiwei <zhiwei_liu@linux.alibaba.com>,
	Helene Chelin <helene.chelin@embecosm.com>,
	Max Chou <max.chou@sifive.com>
Subject: Re: [RFC 2/2] target/riscv: rvv: improve performance of RISC-V vector loads and stores on large amounts of data.
Date: Tue, 10 Sep 2024 11:18:03 -0700	[thread overview]
Message-ID: <41ab786e-87b7-4aa9-a259-cdf5d14003a6@linaro.org> (raw)
In-Reply-To: <1753bd69-6f7a-4b34-a7ae-8a0b225b72c9@embecosm.com>

On 9/10/24 04:20, Paolo Savini wrote:
> Thanks for the feedback Richard, I'm working on the endianness. Could you please give me 
> more details about the atomicity issues you are referring to?

For instance a 32-bit atomic memory operation in the guest must be implemented with a >= 
32-bit atomic memory operation in the host.

The main thing to remember is that memcpy() has no atomicity guarantee.  It could be 
implemented as a byte loop.  Thus you may only use memcpy with guest byte vectors.



r~


  reply	other threads:[~2024-09-10 18:18 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-17 15:30 [RFC 0/2] Improve the performance of unit-stride RVV ld/st on Paolo Savini
2024-07-17 15:30 ` [RFC 1/2] target/riscv: rvv: reduce the overhead for simple RISC-V vector unit-stride loads and stores Paolo Savini
2024-07-26 12:22   ` Daniel Henrique Barboza
2024-07-27  7:13   ` Richard Henderson
2024-07-31 12:38     ` Daniel Henrique Barboza
2024-07-17 15:30 ` [RFC 2/2] target/riscv: rvv: improve performance of RISC-V vector loads and stores on large amounts of data Paolo Savini
2024-07-26 12:27   ` Daniel Henrique Barboza
2024-07-27  7:15   ` Richard Henderson
2024-09-10 11:20     ` Paolo Savini
2024-09-10 18:18       ` Richard Henderson [this message]
2024-07-26 12:31 ` [RFC 0/2] Improve the performance of unit-stride RVV ld/st on Daniel Henrique Barboza

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