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

[Derry Shribman]

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