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| From: | Avi Kivity |
| Subject: | Re: [Qemu-devel] Re: [PATCH] virtio: Use ioeventfd for virtqueue notify |
| Date: | Mon, 04 Oct 2010 10:04:29 +0200 |
| User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Thunderbird/3.1.4 |
On 10/04/2010 03:18 AM, Anthony Liguori wrote:
On 10/03/2010 09:28 AM, Michael S. Tsirkin wrote:This is using eventfd as well.Sorry, I meant irqfd.I've tried using irqfd in userspace. It hurts performance quite a bit compared to doing an ioctl so I would suspect this too.A last_used_idx or similar mechanism should help performance quite a bit on top of ioeventfd too.
Any idea why? While irqfd does quite a bit of extra locking, it shouldn't be that bad.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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