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Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC P
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"" |
Date: |
Tue, 09 Oct 2012 12:36:42 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 |
Il 09/10/2012 11:26, Avi Kivity ha scritto:
> On 10/09/2012 11:08 AM, Stefan Hajnoczi wrote:
>> Here are the steps that have been mentioned:
>>
>> 1. aio fastpath - for raw-posix and other aio block drivers, can we reduce
>> I/O
>> request latency by skipping block layer coroutines?
>
> Is coroutine overhead noticable?
I'm thinking more about throughput than latency. If the iothread
becomes CPU-bound, then everything is noticeable.
>> I'm also curious about virtqueue_pop()/virtqueue_push() outside the QEMU
>> mutex
>> although that might be blocked by the current work around MMIO/PIO dispatch
>> outside the global mutex.
>
> It is, yes.
It should only require unlocked memory map/unmap, not MMIO dispatch.
The MMIO/PIO bits are taken care of by ioeventfd.
Paolo
- Re: [Qemu-devel] [RFC PATCH 00/17] Support for multiple "AIO contexts", Stefan Hajnoczi, 2012/10/08
- Re: [Qemu-devel] [RFC PATCH 00/17] Support for multiple "AIO contexts", Paolo Bonzini, 2012/10/08
- [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Stefan Hajnoczi, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Avi Kivity, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"",
Paolo Bonzini <=
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Avi Kivity, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Paolo Bonzini, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Avi Kivity, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Paolo Bonzini, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Jan Kiszka, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Avi Kivity, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Avi Kivity, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Paolo Bonzini, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Avi Kivity, 2012/10/09
- Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re: [RFC PATCH 00/17] Support for multiple "AIO contexts"", Paolo Bonzini, 2012/10/09