From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39916) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1enmrl-0002Jz-PE for qemu-devel@nongnu.org; Mon, 19 Feb 2018 09:56:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1enmri-0000WI-OG for qemu-devel@nongnu.org; Mon, 19 Feb 2018 09:56:29 -0500 Date: Mon, 19 Feb 2018 15:56:21 +0100 From: Cornelia Huck Message-ID: <20180219155621.3c146fe9.cohuck@redhat.com> In-Reply-To: <1518797321-28356-3-git-send-email-mihajlov@linux.vnet.ibm.com> References: <1518797321-28356-1-git-send-email-mihajlov@linux.vnet.ibm.com> <1518797321-28356-3-git-send-email-mihajlov@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv5 2/5] qmp: add query-cpus-fast List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Viktor Mihajlovski Cc: qemu-devel@nongnu.org, agraf@suse.de, ehabkost@redhat.com, armbru@redhat.com, david@redhat.com, dgilbert@redhat.com, borntraeger@de.ibm.com, qemu-s390x@nongnu.org, pbonzini@redhat.com, rth@twiddle.net, eblake@redhat.com On Fri, 16 Feb 2018 17:08:38 +0100 Viktor Mihajlovski wrote: > From: Luiz Capitulino > > The query-cpus command has an extremely serious side effect: > it always interrupts all running vCPUs so that they can run > ioctl calls. This can cause a huge performance degradation for > some workloads. And most of the information retrieved by the > ioctl calls are not even used by query-cpus. > > This commit introduces a replacement for query-cpus called > query-cpus-fast, which has the following features: > > o Never interrupt vCPUs threads. query-cpus-fast only returns > vCPU information maintained by QEMU itself, which should be > sufficient for most management software needs > > o Drop "halted" field as it can not be retrieved in a fast > way on most architectures > > o Drop irrelevant fields such as "current", "pc" and "arch" > > o Rename some fields for better clarification & proper naming > standard > > Signed-off-by: Luiz Capitulino > Signed-off-by: Viktor Mihajlovski > --- > cpus.c | 38 ++++++++++++++++++++++++++++++ > qapi-schema.json | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 108 insertions(+) Reviewed-by: Cornelia Huck