Messages in this thread |  | | | Date | Thu, 12 Feb 2009 20:44:57 -0700 | | From | Matthew Wilcox <> | | Subject | Re: [PATCH v3 0/6] ATS capability support for Intel IOMMU |
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On Thu, Feb 12, 2009 at 08:50:32PM +0800, Yu Zhao wrote: > 2, avoid using pci_find_ext_capability every time when reading ATS > Invalidate Queue Depth (Matthew Wilcox)
er ... I didn't say it was a problem. I said I couldn't tell if it was a problem. There's no point in taking up an extra 4 bytes per pci_dev if it's not a performance problem. How often do we query the queue depth? Is this something a device driver will call once per device and then remember for itself, or only use at setup? Or is it something we call every millisecond?
-- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."
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