[nvmewin] NVMe Windows driver copy progress issue

[mithun.davis at keysight.com]

Hi Mike,

I did try this out. When copying with /j the command returns only after copy is actually over while when this switch is not used, xcopy returns immediately. So I think you are right, the cause of the issue is buffering.

Is there some way we can prevent buffering for specific drives or can we switch this off in the driver?

Thanks for your help.

Regards,
Mithun

-----Original Message-----
From: nvmewin-bounces at lists.openfabrics.org [mailto:nvmewin-bounces at lists.openfabrics.org] On Behalf Of Mike Berhan
Sent: Saturday, 18 October, 2014 8:39 PM
To: nvmewin at lists.openfabrics.org
Subject: Re: [nvmewin] NVMe Windows driver copy progress issue

That's because you are dealing with buffered writes.  Try using xcopy /j to perform your copy.

http://technet.microsoft.com/en-us/library/cc771254(WS.10).aspx

I wrote a simple batch file to copy a 512MB file from a RAM drive to an NVMe drive and do it 6 times.  These are the timings:

1080 msec (with /j)
280 msec
310 msec
280 msec
2160 msec (with /j)
280 msec

The 5th timing is double the 1st timing because it is now competing for bandwidth from the buffered writes that preceded it.

Mike

From: nvmewin-bounces at lists.openfabrics.org
[mailto:nvmewin-bounces at lists.openfabrics.org] On Behalf Of mithun.davis at keysight.com
Sent: Friday, October 17, 2014 4:13 AM
To: nvmewin at lists.openfabrics.org
Subject: [nvmewin] NVMe Windows driver copy progress issue

Hi,

I am faced with a particular problem with the NVMe driver for Windows. I am using the 1.3 revision of the driver. When I copy a large file onto the device, it appears to have been copied in windows explorer but in the background the driver still seems to be copying it. The device being used is not very fast to respond which is the cause of the slow speed. Can anyone please help with why the file appears to be copied in windows explorer? I would like it to show the copy status as close to actual as possible.

Thanks in advance for your help.

Regards,
Mithun

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