Our suggestion would be to use the maximum (a large enough) value,
so that vhost is polling 100% of the time.
The polling optimization mainly addresses users who want to maximize
their
performance, even on the expense of wasting cpu cycles. The maximum
value
will produce the
Michael S. Tsirkin m...@redhat.com wrote on 12/01/2015 12:36:13 PM:
From: Michael S. Tsirkin m...@redhat.com
To: Razya Ladelsky/Haifa/IBM@IBMIL
Cc: Alex Glikson/Haifa/IBM@IBMIL, Eran Raichstein/Haifa/IBM@IBMIL,
Yossi Kuperman1/Haifa/IBM@IBMIL, Joel Nider/Haifa/IBM@IBMIL,
abel.gor
Hi Razya,
Thanks for the update.
So that's reasonable I think, and I think it makes sense
to keep working on this in isolation - it's more
manageable at this size.
The big questions in my mind:
- What happens if system is lightly loaded?
E.g. a ping/pong benchmark. How much extra CPU
- Forwarded by Razya Ladelsky/Haifa/IBM on 01/01/2015 09:37 AM -
From: Razya Ladelsky/Haifa/IBM@IBMIL
To: m...@redhat.com
Cc:
Date: 25/11/2014 02:43 PM
Subject:Re: Benchmarking for vhost polling patch
Sent by:kvm-ow...@vger.kernel.org
Hi Michael,
Hi Razya
Hi Michael,
Hi Razya,
On the netperf benchmark, it looks like polling=10 gives a modest but
measureable gain. So from that perspective it might be worth it if it's
not too much code, though we'll need to spend more time checking the
macro effect - we barely moved the needle on the macro
Razya Ladelsky/Haifa/IBM@IBMIL wrote on 29/10/2014 02:38:31 PM:
From: Razya Ladelsky/Haifa/IBM@IBMIL
To: m...@redhat.com
Cc: Razya Ladelsky/Haifa/IBM@IBMIL, Alex Glikson/Haifa/IBM@IBMIL,
Eran Raichstein/Haifa/IBM@IBMIL, Yossi Kuperman1/Haifa/IBM@IBMIL,
Joel Nider/Haifa/IBM@IBMIL, abel.gor
Razya Ladelsky/Haifa/IBM@IBMIL wrote on 29/10/2014 02:38:31 PM:
From: Razya Ladelsky/Haifa/IBM@IBMIL
To: m...@redhat.com
Cc: Razya Ladelsky/Haifa/IBM@IBMIL, Alex Glikson/Haifa/IBM@IBMIL,
Eran Raichstein/Haifa/IBM@IBMIL, Yossi Kuperman1/Haifa/IBM@IBMIL,
Joel Nider/Haifa/IBM@IBMIL, abel.gor
Zhang Haoyu zhan...@sangfor.com wrote on 30/10/2014 01:30:08 PM:
From: Zhang Haoyu zhan...@sangfor.com
To: Razya Ladelsky/Haifa/IBM@IBMIL, mst m...@redhat.com
Cc: Razya Ladelsky/Haifa/IBM@IBMIL, kvm kvm@vger.kernel.org
Date: 30/10/2014 01:30 PM
Subject: Re: Benchmarking for vhost polling
Hi Michael,
Following the polling patch thread:
http://marc.info/?l=kvmm=140853271510179w=2,
I changed poll_stop_idle to be counted in micro seconds, and carried out
experiments using varying sizes of this value. The setup for netperf consisted
of
1 vm and 1 vhost , each running on their own
David Laight david.lai...@aculab.com wrote on 21/08/2014 05:29:41 PM:
From: David Laight david.lai...@aculab.com
To: Razya Ladelsky/Haifa/IBM@IBMIL, Michael S. Tsirkin
m...@redhat.com
Cc: abel.gor...@gmail.com abel.gor...@gmail.com, Alex Glikson/
Haifa/IBM@IBMIL, Eran Raichstein/Haifa/IBM
netperf
(4086 MB/sec - 5545 MB/sec).
filebench, 1 vm:
ops/sec improved by 13% with the polling patch. Number of exits
was reduced by
31%.
The same experiment with 3 vms running filebench showed similar
numbers.
Signed-off-by: Razya Ladelsky ra...@il.ibm.com
Gave it a quick try
MB/sec - 5545 MB/sec).
filebench, 1 vm:
ops/sec improved by 13% with the polling patch. Number of exits
was reduced by
31%.
The same experiment with 3 vms running filebench showed similar
numbers.
Signed-off-by: Razya Ladelsky ra...@il.ibm.com
This really needs more thourough
That was just one example. There many other possibilities. Either
actually make the systems load all host CPUs equally, or divide
throughput by host CPU.
The polling patch adds this capability to vhost, reducing costly exit
overhead when the vm is loaded.
In order to load the vm I ran
Hi Michael,
Sorry for the delay, had some problems with my mailbox, and I realized
just now that
my reply wasn't sent.
The vm indeed ALWAYS utilized 100% cpu, whether polling was enabled or
not.
The vhost thread utilized less than 100% (of the other cpu) when
polling
Michael S. Tsirkin m...@redhat.com wrote on 12/08/2014 12:18:50 PM:
From: Michael S. Tsirkin m...@redhat.com
To: David Miller da...@davemloft.net
Cc: Razya Ladelsky/Haifa/IBM@IBMIL, kvm@vger.kernel.org, Alex
Glikson/Haifa/IBM@IBMIL, Eran Raichstein/Haifa/IBM@IBMIL, Yossi
Kuperman1/Haifa
From: Razya Ladelsky ra...@il.ibm.com
Date: Thu, 31 Jul 2014 09:47:20 +0300
Subject: [PATCH] vhost: Add polling mode
When vhost is waiting for buffers from the guest driver (e.g., more packets to
send in vhost-net's transmit queue), it normally goes to sleep and waits for the
guest to kick
Resubmitting the patch in: http://marc.info/?l=kvmm=140594903520308w=2
after fixing the whitespaces issues.
Thank you,
Razya
From f293e470b36ff9eb4910540c620315c418e4a8fc Mon Sep 17 00:00:00 2001
From: Razya Ladelsky ra...@il.ibm.com
Date: Thu, 31 Jul 2014 09:47:20 +0300
Subject: [PATCH
kvm-ow...@vger.kernel.org wrote on 29/07/2014 03:40:18 PM:
From: Michael S. Tsirkin m...@redhat.com
To: Razya Ladelsky/Haifa/IBM@IBMIL,
Cc: abel.gor...@gmail.com, Alex Glikson/Haifa/IBM@IBMIL, Eran
Raichstein/Haifa/IBM@IBMIL, Joel Nider/Haifa/IBM@IBMIL,
kvm@vger.kernel.org, kvm-ow
kvm-ow...@vger.kernel.org wrote on 29/07/2014 04:30:34 AM:
From: Zhang Haoyu zhan...@sangfor.com
To: Jason Wang jasow...@redhat.com, Abel Gordon
abel.gor...@gmail.com,
Cc: Razya Ladelsky/Haifa/IBM@IBMIL, Alex Glikson/Haifa/IBM@IBMIL,
Eran Raichstein/Haifa/IBM@IBMIL, Joel Nider/Haifa/IBM
Michael S. Tsirkin m...@redhat.com wrote on 29/07/2014 11:06:40 AM:
From: Michael S. Tsirkin m...@redhat.com
To: Razya Ladelsky/Haifa/IBM@IBMIL,
Cc: kvm@vger.kernel.org, abel.gor...@gmail.com, Joel Nider/Haifa/
IBM@IBMIL, Yossi Kuperman1/Haifa/IBM@IBMIL, Eran Raichstein/Haifa/
IBM@IBMIL
Hmm there aren't a lot of numbers there :(. Speed increased by 33% but
by how much? E.g. maybe you are getting from 1Mbyte/sec to 1.3,
if so it's hard to get excited about it.
Netperf 1 VM: 1516 MB/sec - 2046 MB/sec
and for 3 VMs: 4086 MB/sec - 5545 MB/sec
Some questions that come to
Jason Wang jasow...@redhat.com wrote on 23/07/2014 08:26:36 AM:
From: Jason Wang jasow...@redhat.com
To: Razya Ladelsky/Haifa/IBM@IBMIL, kvm@vger.kernel.org, Michael S.
Tsirkin m...@redhat.com,
Cc: abel.gor...@gmail.com, Joel Nider/Haifa/IBM@IBMIL, Yossi
Kuperman1/Haifa/IBM@IBMIL, Eran
://www.youtube.com/watch?v=9EyweibHfEs
and
https://www.mail-archive.com/kvm@vger.kernel.org/msg98179.html
Comments are welcome,
Thank you,
Razya
From: Razya Ladelsky ra...@il.ibm.com
Add an optional polling mode to continuously poll the virtqueues
for new buffers, and avoid asking the guest to kick
Hi,
To summarize the issues raised and following steps:
1. Shared vhost thread will support multiple vms, while supporting
cgroups.
As soon as we have a design to support cgroups with multiple vms, we'll
share it.
2. Adding vhost polling mode: this patch can be submitted independently
from
Gleb Natapov g...@minantech.com wrote on 24/12/2013 06:21:03 PM:
From: Gleb Natapov g...@kernel.org
To: Razya Ladelsky/Haifa/IBM@IBMIL,
Cc: Michael S. Tsirkin m...@redhat.com, abel.gor...@gmail.com,
Anthony Liguori anth...@codemonkey.ws, as...@redhat.com,
digitale...@google.com, Eran
Hi,
Thank you all for your comments.
I'm sorry for taking this long to reply, I was away on vacation..
It was a good, long discussion, many issues were raised, which we'd like
to address with the following proposed roadmap for Elvis patches.
In general, we believe it would be best to start with
Michael S. Tsirkin m...@redhat.com wrote on 24/11/2013 12:26:15 PM:
From: Michael S. Tsirkin m...@redhat.com
To: Razya Ladelsky/Haifa/IBM@IBMIL,
Cc: kvm@vger.kernel.org, anth...@codemonkey.ws, g...@redhat.com,
pbonz...@redhat.com, as...@redhat.com, jasow...@redhat.com,
digitale
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