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From: Frederic Konrad <fred.konrad@greensocs.com>
To: qemu-devel <qemu-devel@nongnu.org>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Alex Bennée" <alex.bennee@linaro.org>
Subject: [Qemu-devel] 4 CPUs with vexpress is slow?
Date: Mon, 22 Jun 2015 20:18:36 +0200	[thread overview]
Message-ID: <5588517C.9000909@greensocs.com> (raw)

Hi,

Testing MTTCG patch-set performance I found strange slowness with _upstream_
qemu (46bca5404b08201bb9df1ac32bc88fc7e6db1f74).

Basically booting a vexpress-a15 with "-smp 4" takes approximately 
forever if I use a
vexpress-v2p-ca15-tc1.dtb (2x A15) dtb and 39 secs if I hack this dtb to 
have 4 CPUs.

This is definitely strange because if I use "-smp 2" with the same guest 
image it takes
only 4 secs. And MTTCG patch-set seems to fix the issue as it boot in 6 
secs with
"-smp 4".

Is that a known issue or maybe it's my guest (linux 3.13.5)?

Fred

             reply	other threads:[~2015-06-22 18:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-22 18:18 Frederic Konrad [this message]
2015-06-22 20:57 ` [Qemu-devel] 4 CPUs with vexpress is slow? Peter Maydell
2015-06-22 22:10   ` Frederic Konrad

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