From: earnie_boyd AT hotmail DOT com (Earnie Boyd) Subject: RE: Cygwin Performance - especially on a network 10 Apr 1998 09:20:45 -0700 Message-ID: <19980408162246.18931.qmail.cygnus.gnu-win32@hotmail.com> Content-Type: text/plain To: kh AT wg DOT icl DOT co DOT uk Cc: gnu-win32 AT cygnus DOT com >From: Kevin Hughes >Reply-To: "kh AT wg DOT icl DOT co DOT uk" >To: "'Earnie Boyd'" >Cc: "gnu-win32 AT cygnus DOT com" >Subject: RE: Cygwin Performance - especially on a network >Date: Wed, 8 Apr 1998 13:34:47 +0100 > >Earnie, > sorry about the long delay but I have been refining the measures etc. and >doing other work. That's ok, I've been to busy to notice any delay, except for the mailing list delay. > >The latest set of results for the open/fstat/close sequence are as follows: >(where times are in milliseconds (I hope)) > > >Local file access > > Min "Typical" Max >Gnu/Cygnus 2.8 3.0 4.4 >Gnu/NT 0.73 0.8 1.7 >VC++ 0.75 0.8 2.85 Do you mean "Mingw32" when you say "Gnu/NT"? If so, I can believe it based on packages I've ported to Mingw32. > >Remote file access > > Min "Typical Max >Gnu/Cygnus 10.8 11.0 18.6 >Gnu/NT 3.4 3.5 5.0 >VC++ 3.4 3.5 6.0 > >I have also looked at the file accesses per open/fstat/close Did you catch the "Memory Leak" post concerning open/close? 16 bytes of memory lost per issue of open/close pairs. > > Local Remote >Gnu/Cygnus 20 23 >Gnu/NT 5 7 >VC++ 5 7 > >The cost and accesses ration perfectly - the cost is all down to the extra >accesses that the cygnus layer issues. > Sounds correct to me. >I guess this is all to do with the emulation of the Unix filestore >semantics but I do not understand why. I would have thought that a simple >stat to determine if its a link and then an open would be sufficient - but >I am very naive in this. > >Any information much appreciated. Have a look at the documentation for Win32 stat and fstat. Inode is returned as 0, so cygwin32 emulates it. There is no true "link" on Win32 and lstat isn't supplied in the libraries by MS. File privilege bit masks have to be emulated to the extent of getting a true UNIX filesystem emulation. And, the directory has to be mapped against the cygwin32 mount table to find the file. I'm sure there are other things going on to; but, don't know what as yet. > >Kevin > >PS - I have read that NtOpenFile bypasses the win32 layer and allows mixed >case file names to be passed. > I think that Sergey has already incorporated Mixed Case on NTFS into the cygwin32.dll based on earlier posts. - \\||// ---o0O0--Earnie--0O0o---- -earnie_boyd AT hotmail DOT com- ------ooo0O--O0ooo------- PS: Did you try your test on a FAT file system? ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com - For help on using this list (especially unsubscribing), send a message to "gnu-win32-request AT cygnus DOT com" with one line of text: "help".