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From: Peter Maydell <peter.maydell@linaro.org>
To: BALATON Zoltan <balaton@eik.bme.hu>
Cc: qemu-devel@nongnu.org, qemu-trivial@nongnu.org
Subject: Re: [PATCH] bitops.h: Compile out asserts without --enable-debug
Date: Mon, 22 May 2023 10:16:25 +0100	[thread overview]
Message-ID: <CAFEAcA9gAYPpOJ6VyPYwCVyOhMmJMEe4QyGzB57xCbK0MOED5A@mail.gmail.com> (raw)
In-Reply-To: <20230520205444.887287457E7@zero.eik.bme.hu>

On Sat, 20 May 2023 at 21:55, BALATON Zoltan <balaton@eik.bme.hu> wrote:
>
> The low level extract and deposit funtions provided by bitops.h are
> used in performance critical places. It crept into target/ppc via
> FIELD_EX64 and also used by softfloat so PPC code using a lot of FPU
> where hardfloat is also disabled is doubly affected.
>
> Normally asserts should be compiled out from release builds with
> -DNDEBUG but that cannot be used in QEMU because some places still
> rely on asserts instead of proper error checking. To resolve this,
> compile out asserts from deposit/extract functions in optimised builds
> which improves performance for target/ppc and possibly others too.

Can we have some figures for performance improvements,
please? General QEMU policy is that asserts remain,
even in non-debug builds, so exceptions from that policy
should come with justification with figures attached.

thanks
-- PMM


  reply	other threads:[~2023-05-22  9:17 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-20 20:54 [PATCH] bitops.h: Compile out asserts without --enable-debug BALATON Zoltan
2023-05-22  9:16 ` Peter Maydell [this message]
2023-05-22 12:00   ` BALATON Zoltan
2023-05-22 12:05     ` Peter Maydell
2023-05-22 11:26 ` Alex Bennée
2023-05-22 13:25   ` BALATON Zoltan
2023-05-22 16:48     ` Alex Bennée
2023-05-22 22:26       ` BALATON Zoltan
2023-05-22 23:34         ` Richard Henderson
2023-05-23  6:43           ` Alex Bennée
2023-06-05 22:06             ` BALATON Zoltan

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