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Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions
From: |
Benjamin Herrenschmidt |
Subject: |
Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions |
Date: |
Tue, 22 May 2012 21:41:41 +1000 |
On Tue, 2012-05-22 at 14:14 +0300, Michael S. Tsirkin wrote:
> > The baseline is the laptop without kvm talking to the server. The
> > TCP_STREAM test results are:
>
> It's not a good test. The thing most affecting throughput results is
> how
> much CPU does you guest get. So as a minumum you need to measure CPU
> utilization on the host and divide by that.
The simple fact that we don't reach the baseline while in qemu seems to
be a reasonably good indication that we tend to be CPU bound already so
it's not -that- relevant. It would be if we were saturating the network.
But yes, I can try to do more tests tomorrow, it would be nice if you
could contribute a proper test protocol (or even test on some machines)
since you seem to be familiar with those measurements (and I have a very
limited access to x86 gear ... basically just my laptop).
Cheers,
Ben.
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access function, (continued)
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access function, Rusty Russell, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions, Anthony Liguori, 2012/05/21
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions, Benjamin Herrenschmidt, 2012/05/21
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions, Anthony Liguori, 2012/05/21
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions, Michael S. Tsirkin, 2012/05/21
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions, Benjamin Herrenschmidt, 2012/05/21
- [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Benjamin Herrenschmidt, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Benjamin Herrenschmidt, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Benjamin Herrenschmidt, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Michael S. Tsirkin, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions,
Benjamin Herrenschmidt <=
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Michael S. Tsirkin, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Benjamin Herrenschmidt, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to DMA functions, Anthony Liguori, 2012/05/22
- Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions, Michael S. Tsirkin, 2012/05/21
Re: [Qemu-devel] [PATCH 00/13] IOMMU infrastructure, Anthony Liguori, 2012/05/14