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Re: Cygwin Filesystem Performance degradation 1.7.5 vs 1.7.7, and methods for improving performance


Hi,

>> If so, what is needed is that lstat() will do QIF/QDF() for local
>> shares, and QAF() for network shares.
>
> That doesn't help. It might be a help for outmoded systems like XP, but
> it doesn't differ from QIF on Vista and later. Even for network drives,
> the FASTIO_NETWORK_QUERY_OPEN returns FAST IO DISALLOWED. See the output
> from procmon on W7:
>
> 0 16:59:50,6332763 x.exe 2960 FASTIO_NETWORK_QUERY_OPEN \\calimero\corinna\t3.c FAST IO DISALLOWED
> 1 16:59:50,6349281 x.exe 2960 IRP_MJ_CREATE \\calimero\corinna\t3.c SUCCESS Desired Access: Read Attributes, Disposition: Open, Options: Open Reparse Point, Attributes: n/a, ShareMode: Read, Write, Delete, AllocationSize: n/a, OpenResult: Opened
> 2 16:59:50,6420802 x.exe 2960 FASTIO_QUERY_INFORMATION \\calimero\corinna\t3.c FAST IO DISALLOWED Type: QueryBasicInformationFile
> 3 16:59:50,6421872 x.exe 2960 IRP_MJ_QUERY_INFORMATION \\calimero\corinna\t3.c SUCCESS Type: QueryBasicInformationFile, CreationTime: 13.09.2010 14:02:22, LastAccessTime: 04.10.2010 20:51:32, LastWriteTime: 13.09.2010 14:02:22, ChangeTime: 13.09.2010 14:02:22, FileAttributes: N
> 4 16:59:50,6422788 x.exe 2960 IRP_MJ_CLEANUP \\calimero\corinna\t3.c SUCCESS
> 5 16:59:50,6427853 x.exe 2960 IRP_MJ_CLOSE \\calimero\corinna\t3.c SUCCESS
>
> Note especially that the file gets opened for FILE_READ_ATTRIBUTES
> access only, so this case doesn't differ from what Cygwin does anyway.
>
> It also does not matter whether the drive is mounted via a drive letter
> or if the call uses an UNC path. I don't see that this special case has
> any future.


Hmmm... very strange behavior of CIFS!

Derry


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