From: Richard Henderson <rth@twiddle.net>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: stefanha@redhat.com, mst@redhat.com
Subject: Re: [Qemu-devel] [PATCH] exec: optimize phys_page_set_level
Date: Tue, 02 Jun 2015 21:30:56 -0700 [thread overview]
Message-ID: <556E8300.1010108@twiddle.net> (raw)
In-Reply-To: <1432214398-14990-1-git-send-email-pbonzini@redhat.com>
On 05/21/2015 06:19 AM, Paolo Bonzini wrote:
> memcpy is faster than struct assignment, which copies each bitfield
> individually. Arguably a compiler bug, but memcpy is super-special
> cased anyway so what could go wrong?
>
The compiler has the option of doing the copy either way. Any way to actually
show that the small memcpy is faster? That's one of those things where I'm
sure there's a cost calculation that said per member was better.
r~
next prev parent reply other threads:[~2015-06-03 4:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-21 13:19 [Qemu-devel] [PATCH] exec: optimize phys_page_set_level Paolo Bonzini
2015-05-22 8:01 ` Stefan Hajnoczi
2015-06-03 4:30 ` Richard Henderson [this message]
2015-06-03 7:03 ` Paolo Bonzini
2015-06-03 16:14 ` Michael S. Tsirkin
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