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| From: | Chris Friesen |
| Subject: | Re: [Qemu-devel] is there a limit on the number of in-flight I/O operations? |
| Date: | Mon, 21 Jul 2014 08:59:45 -0600 |
| User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 |
On 07/19/2014 02:45 AM, Benoît Canet wrote:
I think in the throttling case the number of in flight operation is limited by the emulated hardware queue. Else request would pile up and throttling would be inefective. So this number should be around: #define VIRTIO_PCI_QUEUE_MAX 64 or something like than that.
Okay, that makes sense. Do you know how much data can be written as part of a single operation? We're using 2MB hugepages for the guest memory, and we saw the qemu RSS numbers jump from 25-30MB during normal operation up to 120-180MB when running dbench. I'd like to know what the worst-case would be.
Thanks, Chris
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