These are the differences in execution time for SBCL, comparing a call to PROBE-FILE, with IGNORE-ERRORS+TRUENAME. Differences in ECL are more dramatic. I attach a patch file that implements the change I suggested.

Note that in order to produce this patch I had to add a workaround: ASDF calls truenamize with wildcard paths without really caring for the location of wildcards. My wrapper checks for those wildcards, refusing to produce a truename but avoiding to signal an error, which is more efficient -- but it all looks fragile and not future proof.

Juanjo

(defun test1 ()
  (dotimes (i 100000)
    (probe-file "Inexistent file")))

(defun test2 ()
  (dotimes (i 100000)
    (ignore-errors (truename "Inexistent file"))))

(time (test1))
Evaluation took:
  2.227 seconds of real time
  2.171720 seconds of total run time (1.786088 user, 0.385632 system)
  [ Run times consist of 0.028 seconds GC time, and 2.144 seconds non-GC time. ]
  97.53% CPU
  5,319,066,321 processor cycles
  319,996,672 bytes consed

(time (test2))
Evaluation took:
  3.371 seconds of real time
  3.303481 seconds of total run time (2.888650 user, 0.414831 system)
  [ Run times consist of 0.044 seconds GC time, and 3.260 seconds non-GC time. ]
  97.98% CPU
  8,055,475,317 processor cycles
  470,401,824 bytes consed


On Fri, Jul 16, 2010 at 11:35 PM, Juan Jose Garcia-Ripoll <juanjose.garciaripoll@googlemail.com> wrote:
On Fri, Jul 16, 2010 at 12:54 AM, edgar <edgar-rft@web.de> wrote:
I think the main problem here is that some implementations
(notably CLISP) differ between files and directories, so
PROBE-FILE cannnot be used to probe files AND directories.

Well, SBCL and ECL do not have that problem, AFAIK. But TRUENAMIZE also seems to be used with files, not directories, from what I could gather during the debugging of ASDF. I would abstract those calls into a function PROBE-FILE-AND-DIRECTORY and use PROBE-FILE internally in this function. The purpose would be clear and sensible  implementations might profit from that -- maybe the terrible startup times for ASDF might be decreased this way.

Juanjo

--
Instituto de Física Fundamental, CSIC
c/ Serrano, 113b, Madrid 28006 (Spain)
http://juanjose.garciaripoll.googlepages.com



--
Instituto de Física Fundamental, CSIC
c/ Serrano, 113b, Madrid 28006 (Spain)
http://juanjose.garciaripoll.googlepages.com