From mboxrd@z Thu Jan 1 00:00:00 1970 From: jik-cygwin@curl.com To: lhall@rfk.com Cc: cygwin@cygwin.com Subject: Re: Optimizing away "ReadFile" calls when Make calls stat() Date: Tue, 13 Feb 2001 11:01:00 -0000 Message-id: <20010213190131.14369.qmail@lizard.curl.com> References: <4.3.1.2.20010213134821.019a7130@pop.ma.ultranet.com> X-SW-Source: 2001-02/msg00674.html > Date: Tue, 13 Feb 2001 13:51:50 -0500 > From: "Larry Hall (RFK Partners, Inc)" > > I know this would only address half the problem but I wonder if it would make > sense to cache the results of ReadFile() so that separate checks for symbolic > links and executables would result in only 1 ReadFile() call. This seems > like a nice general optimization which wouldn't be so "gross"... I see three problems with that: 1) The cache would have to be automatically invalidated whenever the file is changed, and you'd thus need to check if a file has changed before using the cache, and those checks would themselves take time. 2) Many of our dependencies are checked over and over again in many Makefiles by many different Make processes. Thus, either the cache you propose would have to be global in the Cygwin shared memory segment, or the checks would still happen over and over for us. 3) The implementation of such a global cache would be much more complex then the simple changes I implemented in only a couple of hours, and I would argue that this complexity would in fact make such a cache *more* "gross" than the changes I'm suggesting. jik -- Want to unsubscribe from this list? Check out: http://cygwin.com/ml/#unsubscribe-simple