From: Peter Maydell <peter.maydell@linaro.org>
To: Mark Burton <mark.burton@greensocs.com>
Cc: mttcg@listserver.greensocs.com,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Alexander Graf" <agraf@suse.de>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Lluís Vilanova" <vilanova@ac.upc.edu>,
"KONRAD Frédéric" <fred.konrad@greensocs.com>
Subject: Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*.
Date: Wed, 17 Dec 2014 11:19:03 +0000 [thread overview]
Message-ID: <CAFEAcA-4YPa-v35kZ5hrw5Sb5jKXvgKUSXpgDHzMHnBo19FScg@mail.gmail.com> (raw)
In-Reply-To: <8B6B4BF9-3400-4125-8571-F4EF9F12AA89@greensocs.com>
On 17 December 2014 at 11:12, Mark Burton <mark.burton@greensocs.com> wrote:
> We were not (yet) trying to fix that, we were simply asking the
> question, if we add these mutex’s - do we have any detrimental impact
> on anything.
> Seems like the answer is that adding the mutex’s is fine - it doesn’t
> seem to have a performance impact or anything. Good.
Personally I dislike the mutex approach because it means that every
target ends up with its own ad-hoc implementation of something that
would be better implemented in the QEMU core support (even if that
core support is simply taking mutexes in the end).
I also note that the linux-user code for handling exclusives does it
by having a region (effectively) where all other CPUs stop executing
*anything*. Do we need that?
PS: you'll find that we already have some ancient and half-broken
support code for the mutex approach (search for 'spinlock_t')...
-- PMM
prev parent reply other threads:[~2014-12-17 11:19 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-16 9:13 [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_* fred.konrad
2014-12-16 9:31 ` Paolo Bonzini
2014-12-16 9:36 ` Frederic Konrad
2014-12-16 9:49 ` Paolo Bonzini
2014-12-16 9:54 ` Frederic Konrad
2014-12-16 16:37 ` Peter Maydell
2014-12-17 10:27 ` Frederic Konrad
2014-12-17 10:28 ` Alexander Graf
2014-12-17 10:31 ` Mark Burton
2014-12-17 10:45 ` Alexander Graf
2014-12-17 11:12 ` Mark Burton
2014-12-17 11:18 ` Alexander Graf
2014-12-17 11:25 ` Paolo Bonzini
2014-12-17 11:36 ` Peter Maydell
2014-12-17 16:17 ` Mark Burton
2014-12-17 16:27 ` Peter Maydell
2014-12-17 16:29 ` Mark Burton
2014-12-17 16:39 ` Peter Maydell
2014-12-17 16:51 ` Peter Maydell
2014-12-18 9:12 ` Mark Burton
2014-12-18 12:24 ` Alexander Graf
2014-12-18 12:35 ` Dr. David Alan Gilbert
2014-12-18 13:28 ` Paolo Bonzini
2014-12-18 13:56 ` Mark Burton
2014-12-18 14:20 ` Mark Burton
2014-12-18 14:44 ` Alexander Graf
2014-12-18 14:51 ` Mark Burton
2014-12-18 15:05 ` Alexander Graf
2014-12-18 15:09 ` Mark Burton
2014-12-18 16:55 ` Paolo Bonzini
2014-12-17 15:52 ` Mark Burton
2014-12-17 16:20 ` Dr. David Alan Gilbert
2014-12-17 11:19 ` Peter Maydell [this message]
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