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From: | Richard Henderson |
Subject: | Re: [Qemu-devel] [PATCH] exec: optimize phys_page_set_level |
Date: | Tue, 02 Jun 2015 21:30:56 -0700 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
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~
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