From: Richard Henderson <richard.henderson@linaro.org>
To: Robert Hoo <robert.hu@linux.intel.com>,
qemu-devel@nongnu.org, pbonzini@redhat.com, laurent@vivier.eu,
philmd@redhat.com, berrange@redhat.com
Cc: robert.hu@intel.com
Subject: Re: [PATCH 2/2] util: add util function buffer_zero_avx512()
Date: Mon, 24 Feb 2020 08:13:06 -0800 [thread overview]
Message-ID: <7b8fd7a0-9cb8-aab8-0f1b-4a77dd7a6378@linaro.org> (raw)
In-Reply-To: <160d077042713fc46b36650946712a43e6e89b51.camel@linux.intel.com>
On 2/23/20 11:07 PM, Robert Hoo wrote:
> Inspired by your suggestion, I'm thinking go further: use immediate
> rather than a global variable, so that saves 1 memory(/cache) access.
>
> #ifdef CONFIG_AVX512F_OPT
> #define OPTIMIZE_LEN 256
> #else
> #define OPTIMIZE_LEN 64
> #endif
With that, the testing in tests/test-bufferiszero.c, looping through the
implementations, is invalidated. Because once you start compiling for avx512,
you're no longer testing sse2 et al with the same inputs.
IF we want to change the length to suit avx512, we would want to change it
unconditionally. And then you could also tidy up avx2 to avoid the extra
comparisons there.
r~
next prev parent reply other threads:[~2020-02-24 16:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 7:52 [PATCH 0/2] Add AVX512F optimization option and buffer_zero_avx512() Robert Hoo
2020-02-13 7:52 ` [PATCH 1/2] configure: add configure option avx512f_opt Robert Hoo
2020-02-13 7:52 ` [PATCH 2/2] util: add util function buffer_zero_avx512() Robert Hoo
2020-02-13 10:30 ` Paolo Bonzini
2020-02-13 11:58 ` Robert Hoo
2020-02-13 18:20 ` Richard Henderson
2020-02-24 7:07 ` Robert Hoo
2020-02-24 16:13 ` Richard Henderson [this message]
2020-02-25 7:34 ` Robert Hoo
2020-02-25 15:29 ` Richard Henderson
2020-02-13 8:40 ` [PATCH 0/2] Add AVX512F optimization option and buffer_zero_avx512() no-reply
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