WriteFile() whacks st_atime patch
Jason Tishler
jason@tishler.net
Mon Sep 10 12:43:00 GMT 2001
Attached is a cleaned up version of the WriteFile() patch that I
previously posted to cygwin-developers:
http://www.cygwin.com/ml/cygwin-developers/2001-09/msg00076.html
Note that this version only affects disk files. Additionally, I verified
that mutt finds new mail even when not configured with --enable-buffy-size
(Use file size attribute instead of access time).
I ran some tests to determine the performance impact. On my machine,
the GetFileTime()/SetFileTime() pair will add approximately 200 us to
every write. I don't know whether or not better Posix conformance is
worth this performance hit?
Unfortunately, I did not address the race condition between a writer
and a reader. If the reader happens to read while the writer is between
the GetFileTime() and SetFileTime() in fhandler_disk_file::raw_write(),
then the new functionality will actually whack st_atime! So, is it
better to whack st_atime on every write or only on the occasion when
the above mentioned race condition occurs?
Given the above problems, I have very mixed feelings about this patch.
Is it worth pursuing or should I dropped it?
Thanks,
Jason
More information about the Cygwin-patches
mailing list