Re: Abysmal HDD/USB write speed after sleep on a UEFI system

[Alan Stern]

On Tue, 12 Feb 2013, Bjorn Helgaas wrote:

> [+cc linux-pci, Rafael, Alan]
> 
> [https://bugzilla.kernel.org/show_bug.cgi?id=53551]
> 
> On Tue, Feb 12, 2013 at 1:13 PM, Artem S. Tashkinov <t.artem@xxxxxxxxx> wrote:
> > Feb 13, 2013 01:32:53 AM, Linus Torvalds wrote:
> > On Tue, Feb 12, 2013 at 10:29 AM, Artem S. Tashkinov wrote:
> >>> Feb 12, 2013 11:30:20 PM, Linus Torvalds wrote:
> >>>>
> >>>>A few things to try to pinpoint:
> >>>>
> >>>> (a) Is it *only* write performance that suffers, or is it other
> >>>>performance too? Networking (DMA? Perhaps only writing *to* the
> >>>>network?)? CPU?
> >>>
> >>> I  've tested hdpard -tT --direct and the output on boot and after suspend
> >>> is quite similar.
> >>>
> >>> I  've also checked my network read/write speed, and it  's the same
> >>> ~ 100MBit/sec (I have no 1Gbit computers on my network
> >>> unfortunately).
> >>
> >>Ok. So it really sounds like just USB and HD writes. Which is quite
> >>odd, since they have basically nothing in common I can think of
> >>(except the obvious block layer issues).

There's a slight chance that we might get some ideas by comparing
usbmon traces showing disk activity before and after the
problem-causing suspend.

Alan Stern

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