From: Richard Henderson <rth@twiddle.net>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Yongbok Kim <yongbok.kim@imgtec.com>,
Leon Alrae <leon.alrae@imgtec.com>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH 3/3] tcg: Add MO_ALIGN, MO_UNALN
Date: Wed, 13 May 2015 14:19:07 -0700 [thread overview]
Message-ID: <5553BFCB.5060206@twiddle.net> (raw)
In-Reply-To: <CAFEAcA_Hctv-Y-GdjoMUy6q88CmMeodfDiLw3+PJjMmUHkJZKQ@mail.gmail.com>
On 05/13/2015 02:15 PM, Peter Maydell wrote:
> On 13 May 2015 at 22:08, Richard Henderson <rth@twiddle.net> wrote:
>>> Are unaligned accesses always slow-path, by the way?
>
> Would it be in theory possible to fast-path MO_UNALN
> unaligned accesses if the host CPU supported unaligned
> accesses for whatever load/store insn we use in the TLB
> hit case?
We would also need to test for page boundary crossing. That would take at
least 3 more insns, for a host that natively supports unaligned accesses.
Whether that's worth it or not would need testing...
r~
prev parent reply other threads:[~2015-05-13 21:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-13 19:09 [Qemu-devel] [RFC 0/3] Per-memory-op alignment checks Richard Henderson
2015-05-13 19:09 ` [Qemu-devel] [PATCH 1/3] tcg: Merge memop and mmu_idx parameters to qemu_ld/st Richard Henderson
2015-05-13 20:46 ` Peter Maydell
2015-05-13 20:49 ` Richard Henderson
2015-05-13 19:09 ` [Qemu-devel] [PATCH 2/3] tcg: Push merged memop+mmu_idx parameter to softmmu routines Richard Henderson
2015-05-13 20:54 ` Peter Maydell
2015-05-13 21:06 ` Richard Henderson
2015-05-13 21:12 ` Peter Maydell
2015-05-13 19:10 ` [Qemu-devel] [PATCH 3/3] tcg: Add MO_ALIGN, MO_UNALN Richard Henderson
2015-05-13 21:04 ` Peter Maydell
2015-05-13 21:08 ` Richard Henderson
2015-05-13 21:15 ` Peter Maydell
2015-05-13 21:19 ` Richard Henderson [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5553BFCB.5060206@twiddle.net \
--to=rth@twiddle.net \
--cc=leon.alrae@imgtec.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=yongbok.kim@imgtec.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).