Hi Eric, Thanks for the reply.
The triple stat() issue I am talking about is a thread/patch that I read from the 2002 timeframe. I don't think the patch got integrated back tho. http://sourceware.org/ml/cygwin/2002-05/msg01600.html There was another thread that I can't find right now. Actually Linux readdir doesn't provide any clues about the file either, it returns the dirent structure. However, this really opens my eyes as to the problem : > operations, the result of which is just discarded). With directories in > particular, part of the slowdown is that stat()'s st_nlink field is > populated by counting how many files appear in that sub-directory, even > though readline didn't care about that. I had the same issue with a tab in /cygdrive/c/ (obviously due to the nasty-ness of the Windows directory). My directory of 300 subdirectories has umpteen files in the subdirectories. What about turning this subdirectory parsing off by feeding a -1 in st_nlink in Cygwin? How could I propose such a change for cygwin? Thanks again > According to Christopher Wingert on 3/25/2007 8:35 AM: > > Hi > > > > I have a directory where there are about 300 subdirectories in it. When I > > hit tab, not only is the delay to the "Display all 300 possibilities..." > > is slow but the screw draw after answer y is almost like a 300 baud modem. > > I've read on these lists about the triple stat issue with cygwin, is this > > the cause of this problem? Any solution to this problem? > What 'triple stat' issue are you referring to? Part of the problem is > that tab completion relies on determining file type (directory vs. regular > file, etc.), but unlike Linux, cygwin readdir() does not convey file type > (because it is a relatively expensive operation for some file types, such > as symlinks vs. block and character devices, involving opening the file, > which would penalize readdir for other cases), while stat() conveys more > information than readline cares about (involving even MORE expensive > operations, the result of which is just discarded). With directories in > particular, part of the slowdown is that stat()'s st_nlink field is > populated by counting how many files appear in that sub-directory, even > though readline didn't care about that. And part of the problem is that > Windows just STINKS at enumerating directory contents. Overall, it means > that where there are 300 subdirectories, and readline is stat()ing all 300 > of them, cygwin ends up using Windows slow traversal of all 300 > directories. > If readdir were to provide d_type in struct dirent, even populating it > only with DT_DIR vs. DT_UNKNOWN, then readline's tab completion and > several of the coreutils would gain some speedups, merely by being able to > distinguish directories from other files without having to stat() > directories. But SHTDI and write such a patch, and prove that it doesn't > penalize other uses of readdir that could care less about file type. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
