usage info and comments

scheme/httpd/surflets/profile.scm

@@ -1,8 +1,73 @@
-;; Does profiling things, mainly space measurements
+;; Does space measurements using spatial
 ;; Copyright Andreas Bernauer, 2002
 
+;;; Entry points:
+;;;
+;;; (PROFILE-SPACE [file-name])
+;;; 
+;;; Save output of (SPACE) to a file. The file is either a (fresh)
+;;; temporary file (created with CREATE-TEMP-FILE) or the one
+;;; specified by FILE-NAME. In either cases the FILE-NAME is returned.
+;;;
+;;;
+;;; (PROFILE-RESULT file-name nth)
+;;; 
+;;; Return the result of the NTH output in the file named FILE-NAME as
+;;; as SPACE-INFO object (see below for SPACE-INFO).
+;;;
+;;;
+;;; (PROFILE-RESULTS file-name)
+;;;
+;;; Perform a repeated PROFILE-RESULT on FILE-NAME, returning a list
+;;; that contains all SPACE-INFO objects (see below for SPACE-INFO).
+;;;
+;;;
+;;; (MAKE-GNUPLOT-DATA output-file selector space-info-list)
+;;;
+;;; Creates a file named OUTPUT-FILE out of SPACE-INFO-LIST. The
+;;; created file can be used with GNUPLOT (external program, not part
+;;; of SUnet, http://www.gnuplot.info/) to create plot images.
+;;; SELECTOR is a procedure that gets a SPACE-INFO object and returns
+;;; an integer number. See below for possible SELECTORS on SPACE-INFO
+;;; objects.
+;;;
+;;;
+;;; SPACE-INFO object
+;;;
+;;; A container for all the information (SPACE) returns. Try 
+;;;
+;;; > ,open spatial
+;;; > (space)
+;;;
+;;; to see, what I mean. See the following record definition for
+;;; selectors and mutators. The lists returned by the selectors may be
+;;; inspected with PURE-COUNT, PURE-BYTES, IMPURE-COUNT, IMPURE-BYTES,
+;;; TOTAL-COUNT, TOTAL-BYTES
+;;;
+;;;
+;;; Possible strategy to profile space usage: Spread calls to
+;;; PROFILE-SPACE throughout your program. After you've finished, call
+;;; PROFILE-RESULTS and feed the resulting list into
+;;; WRITE-GNUPLOT-DATA-FILE. Run GNUPLOT (external program) with this
+;;; file to get a plot image.
+;;;
+;;;
+;;;
+;;; Example:
+;;; (write-gnuplot-data-file "result.dat"
+;;;                          (lambda (space-info)
+;;;                           (total-bytes (space-info-total space-info)))
+;;;                          (profile-results "concatenated-profile-files"))
+;;;
+;;; in GNUPLOT:
+;;; set terminal png
+;;; set output "result.png"
+;;; plot "result.dat" title "My profile" with lines
+
+
 (define *debug* #f)
 
+;; SPACE-INFO
 (define-record-type space-info :space-info
   (make-space-info pair symbol vector closure location cell channel port 
 		   ratnum record continuation extended-number template 
@@ -32,6 +97,7 @@
   (bignum space-info-bignum set-space-info-bignum!)
   (total space-info-total set-space-info-total!))
 
+;; FIELD-INSPECTORS
 (define pure-count first)
 (define pure-bytes second)
 (define impure-count third)
@@ -41,9 +107,8 @@
 
 
 (define *run-count* 0)
-(define (set-run-count! x)
-  (set! *run-count* x))
 
+;; PROFILE-SPACE writes result of call to (SPACE) to a file
 (define (profile-space . maybe-file-name)
   (let ((file-name
 	 (:optional maybe-file-name
@@ -55,13 +120,48 @@
       (close out))
     file-name))
 
-
+;; PROFILE-RESULT returns a SPACE-INFO object representing the output
+;; of (SPACE) of the NTH run. If there is no such run, 'EOF is returned.
 (define (profile-result file-name nth)
   (let* ((in (open-input-file file-name))
 	 (result (get-space-info in nth)))
     (close in)
     result))
 
+;; PROFILE-RESULTS returns a list of all SPACE-INFO objects that may
+;; be represented in FILE-NAME.
+(define (profile-results file-name)
+  (let ((in (open-input-file file-name)))
+    (let loop ((space-info (get-space-info in 'first))
+	       (result '()))
+      (if (eq? 'eof space-info)
+	  (reverse result)
+	  (loop (get-space-info in 'first)
+		(cons space-info result))))))
+      
+
+;; WRITE-GNUPLOT-DATA-FILE converts a SPACE-INFO-LIST into a data file
+;; for a simple 2D plot, readable by GNUPLOT (external program, not
+;; part of SUnet, http://www.gnuplot.info/)
+(define (write-gnuplot-data-file output-file selector space-info-list)
+  (let ((out (open-output-file output-file)))
+    (display "# generated by profile.scm\n" out)
+    (let loop ((count 0)
+	       (space-info-list space-info-list))
+      (if (null? space-info-list)
+	  (close out)
+	  (begin
+	    (display count out)
+	    (display " " out)
+	    (display (selector (car space-info-list)) out)
+	    (newline out)
+	    (loop (+ 1 count)
+		  (cdr space-info-list)))))))
+
+;; GET-SPACE-INFO returns the result of the NTH call to (SPACE) stored
+;; in IN. If NTH is 'FIRST, the SPACE-INFO object representing the
+;; next run is returned. If EOF is reached before a run is found, 'EOF
+;; is returned.
 (define (get-space-info in nth)
   (if (eof-object? (skip-runs in nth))
       'eof
@@ -92,19 +192,26 @@
 	   (get-record "bignum" assoc-list)
 	   (get-record "total" assoc-list))))))
 
+;; GET-RECORD returns the data of the element in ASSOC-LIST indexed by KEY.
 (define (get-record key assoc-list)
   (let ((record (assoc key assoc-list)))
     (if record 
 	(cdr record)
 	(error "wrong data format - field missing" 'pair))))
 
+;; SKIP-HEADERS just skips two lines in IN (the header lines of a
+;; (SPACE) outpout)
 (define (skip-headers in)
   (read-line in)
   (read-line in))
 
-;; skip runs until write-out is reached
+;; RUN-REGEXP matches the run number in the output file of
+;; PROFILE-SPACE
 (define run-regexp (rx "Run #" (submatch (* digit))))
 
+;; SKIP-RUNS goes forward in IN, until a run in IN with number NTH is
+;; found. If NTH is 'FIRST, just the next reachable run is reached. If
+;; EOF occurs while searching, 'EOF is returned.
 (define (skip-runs in nth)
   (let loop ((line (read-line in)))
     (if (eof-object? line)
@@ -116,10 +223,15 @@
 			  nth)))
 	      #t
 	      (loop (read-line in)))))))
-  
+
+;; TRIM-STRING->NUMBER returns the number stored in S, perhaps padded
+;; with spaces on its left: (TRIM-STRING->NUMBER " 123") ==> 123
 (define (trim-string->number s)
   (string->number (string-trim s)))
 
+;; READ-DATA parses the output of (SPACES). It expects the next line
+;; in IN to be the first data line (not a header). It returns an
+;; a-list (row name . data-list)
 (define (read-data in)
   (let loop ((count 0)
 	     (line (read-line in))
@@ -140,27 +252,3 @@
 	       assoc-list))
 	assoc-list)))
 
-(define (profile-results file-name)
-  (let ((in (open-input-file file-name)))
-    (let loop ((space-info (get-space-info in 'first))
-	       (result '()))
-      (if (eq? 'eof space-info)
-	  (reverse result)
-	  (loop (get-space-info in 'first)
-		(cons space-info result))))))
-      
-	
-(define (make-gnuplot-data output-file selector space-info-list)
-  (let ((out (open-output-file output-file)))
-    (display "# generated by profile.scm\n" out)
-    (let loop ((count 0)
-	       (space-info-list space-info-list))
-      (if (null? space-info-list)
-	  (close out)
-	  (begin
-	    (display count out)
-	    (display " " out)
-	    (display (selector (car space-info-list)) out)
-	    (newline out)
-	    (loop (+ 1 count)
-		  (cdr space-info-list)))))))