From: Paolo Bonzini <pbonzini@redhat.com>
To: Oscar Garcia <oscar@softlab.cs.tsukuba.ac.jp>, kvm@vger.kernel.org
Subject: Re: VMEXIT and Threads
Date: Mon, 06 Oct 2014 08:51:10 +0200 [thread overview]
Message-ID: <54323BDE.6040309@redhat.com> (raw)
In-Reply-To: <54321E64.8070306@softlab.cs.tsukuba.ac.jp>
Il 06/10/2014 06:45, Oscar Garcia ha scritto:
>
> I have a host with debian 7 (intel i7 - RAM 8GB), the guest OS is also
> debian. I am running a program with some threads, every thread makes a
> vmexit call. Also every thread runs in a isolated vcpu. The problem is
> that the program does not run fluently, it looks like that every thread
> interfere with each other. This situation does not happen when
> separately processes call vmexit simultaneously. The question is: there
> is any restriction (any lock) that block the threads. I am not sure
> maybe libc, RCU, on even Qemu and KVM?
At the KVM level, _most_ VCPU ioctls can run concurrently because they
only take a VCPU-level mutex.
QEMU however will take a global mutex on each exit to userspace. What
vmexits are these?
Paolo
next prev parent reply other threads:[~2014-10-06 6:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-06 4:45 VMEXIT and Threads Oscar Garcia
2014-10-06 6:51 ` Paolo Bonzini [this message]
2014-10-06 7:29 ` Jan Kiszka
2014-10-06 19:07 ` Marcelo Tosatti
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