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From: Jiaqing Du <jiaqing@gmail.com>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] Question on cpu_interrupt()
Date: Thu, 29 Apr 2010 18:22:24 +0200	[thread overview]
Message-ID: <z2g6d8082041004290922ob022478bke1d1b99277da714e@mail.gmail.com> (raw)

Hi,

I am trying to inject NMIs to a guest running in QEMU by using
cpu_interrupt(). I notice that QEMU slows down significantly when NMIs
are being injected.

The injected NMIs per second is around 10. QEMU is pined to one core.
A computation intensive application runs in the guest. When no NMIs
are being injected, the physical CPU utilization is 100%; while NMIs
are injected by calling cpu_interrupt(), the physical CPU utilization
rate drops to around 30%. As far as I know from reading the code,
cpu_interrupt() unchains the translation cache. So when the current TB
is executed over, QEMU code is executed to handle the interrupt. I
also notice that cpu_interrupt() is called very frequently normally.
Why QEMU's performance drops so much when NMIs are being injected?

Please CC me your reply.


Thanks,
Jiaqing

                 reply	other threads:[~2010-04-29 16:22 UTC|newest]

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