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From: Juan Quintela <quintela@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-devel@nongnu.org,  peter.maydell@linaro.org
Subject: Re: [PATCH 5/9] util/bufferiszero: Use i386 cpuinfo.h
Date: Thu, 18 May 2023 11:49:11 +0200	[thread overview]
Message-ID: <87r0redl60.fsf@secure.mitica> (raw)
In-Reply-To: <20230518044058.2777467-6-richard.henderson@linaro.org> (Richard Henderson's message of "Wed, 17 May 2023 21:40:54 -0700")

Richard Henderson <richard.henderson@linaro.org> wrote:
> Use cpuinfo_init() during init_accel(), and the variable cpuinfo
> during test_buffer_is_zero_next_accel().  Adjust the logic that
> cycles through the set of accelerators for testing.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Semi related to this.

For migration, I check every single page to see if it is full of zeros.
But I can promisse that it is just a page (i.e. 4KiB, 16KiB or 64KiB,
correct alignation, correct length, ...).

Will do it make sense to have an special function for that?

Yes, I have found with perf that bufferiszero() is quite high.  No, I
haven't try to experiment using a function that is optimized for the
page size in the architecture.

What do you think?

Later, Juan.



  reply	other threads:[~2023-05-18  9:49 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-18  4:40 [PATCH 0/9] Host-specific includes, begin cpuinfo.h Richard Henderson
2023-05-18  4:40 ` [PATCH 1/9] util: Introduce host-specific cpuinfo.h Richard Henderson
2023-05-18  9:30   ` Juan Quintela
2023-05-18  4:40 ` [PATCH 2/9] util: Add cpuinfo-i386.c Richard Henderson
2023-05-18  9:35   ` Juan Quintela
2023-05-18 12:45     ` Richard Henderson
2023-05-18  4:40 ` [PATCH 3/9] util: Add i386 CPUINFO_ATOMIC_VMOVDQU Richard Henderson
2023-05-18 15:52   ` Peter Maydell
2023-05-18  4:40 ` [PATCH 4/9] tcg/i386: Use cpuinfo.h Richard Henderson
2023-05-18 15:53   ` Peter Maydell
2023-05-18  4:40 ` [PATCH 5/9] util/bufferiszero: Use i386 cpuinfo.h Richard Henderson
2023-05-18  9:49   ` Juan Quintela [this message]
2023-05-18 12:48     ` Richard Henderson
2023-05-18  4:40 ` [PATCH 6/9] migration/xbzrle: Shuffle function order Richard Henderson
2023-05-18  9:19   ` Juan Quintela
2023-05-18  4:40 ` [PATCH 7/9] migration/xbzrle: Use i386 cacheinfo.h Richard Henderson
2023-05-18  9:44   ` Juan Quintela
2023-05-18  4:40 ` [PATCH 8/9] migration: Build migration_files once Richard Henderson
2023-05-18  9:20   ` Juan Quintela
2023-05-18  4:40 ` [PATCH 9/9] util: Add cpuinfo-aarch64.c Richard Henderson
2023-05-18 15:55   ` Peter Maydell

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