From 7ceebf7a23d7839bb47acac267864ad1a11e114a Mon Sep 17 00:00:00 2001
From: Vincent St-Amour <stamourv@racket-lang.org>
Date: Thu, 30 May 2013 16:13:34 -0400
Subject: [PATCH] First attempt at a contract profiler.

Breaks down time spent in contracts by contract, callee, etc.

Note: Original version dates from Jan/Feb, but I rewrote the git history.
---
 collects/profile/contract-profile.rkt | 112 ++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 collects/profile/contract-profile.rkt

diff --git a/collects/profile/contract-profile.rkt b/collects/profile/contract-profile.rkt
new file mode 100644
index 0000000000..ab668626d4
--- /dev/null
+++ b/collects/profile/contract-profile.rkt
@@ -0,0 +1,112 @@
+#lang racket/base
+
+(require racket/list unstable/list racket/match
+         racket/contract
+         (only-in racket/contract/private/guts contract-continuation-mark-key)
+         "sampler.rkt")
+
+(struct contract-profile
+  (total-time n-samples n-contract-samples
+   ;; (pairof blame? profile-sample)
+   ;; samples taken while a contract was running
+   live-contract-samples
+   ;; (listof blame?)
+   ;; all the blames that were observed during sampling
+   all-blames))
+
+;; (listof (U blame? #f)) profile-samples -> contract-profile struct
+(define (correlate-contract-samples contract-samples samples*)
+  (define total-time (car samples*))
+  (define samples    (cdr samples*))
+  (define n-samples             (length contract-samples))
+  ;; combine blame info and stack trace info. samples should line up
+  (define aug-contract-samples  (map cons contract-samples samples))
+  (define live-contract-samples (filter car aug-contract-samples))
+  (define n-contract-samples    (length live-contract-samples))
+  (define all-blames (remove-duplicates (filter values contract-samples)))
+  (contract-profile total-time n-samples n-contract-samples
+                    live-contract-samples all-blames))
+
+
+(define (analyze-contract-samples contract-samples samples*)
+  (define correlated (correlate-contract-samples contract-samples samples*))
+  (print-breakdown correlated))
+
+
+(define (print-breakdown correlated)
+  (match-define (contract-profile total-time n-samples n-contract-samples
+                                  live-contract-samples all-blames)
+    correlated)
+
+  (printf "Running time is ~a% contracts (~a/~a samples).\n\n"
+          (* 100 (/ n-contract-samples n-samples 1.0))
+          n-contract-samples n-samples)
+
+  (define (print-contract/loc c)
+    (printf "~a @ ~a\n" (blame-contract c) (blame-source c)))
+
+  (displayln "\nBY CONTRACT\n")
+  (define samples-by-contract
+    (sort (group-by equal? live-contract-samples
+                    #:key (lambda (x) (blame-contract (car x))))
+          > #:key length #:cache-keys? #t))
+  (for ([c (in-list samples-by-contract)])
+    (define representative (caar c))
+    (print-contract/loc representative)
+    (printf "  ~a samples\n\n" (length c)))
+
+  (displayln "\nBY CALLEE\n")
+  (for ([g (in-list samples-by-contract)])
+    (define representative (caar g))
+    (print-contract/loc representative)
+    (for ([x (sort
+              (group-by equal? g
+                        #:key (lambda (x) (blame-value (car x)))) ; callee source, maybe
+              > #:key length)])
+      (printf "  ~a\n  ~a samples\n" (blame-value (caar x)) (length x)))
+    (newline))
+
+  (define samples-by-contract-by-caller
+    (for/list ([g (in-list samples-by-contract)])
+      (sort (group-by equal? (map sample-prune-stack-trace g)
+                      #:key cdddr) ; pruned stack trace
+            > #:key length)))
+
+  (displayln "\nBY CALLER\n")
+  (for* ([g samples-by-contract-by-caller]
+         [c g])
+    (define representative (car c))
+    (print-contract/loc (car representative))
+    (for ([frame (in-list (cdddr representative))])
+      (printf "  ~a @ ~a\n" (car frame) (cdr frame)))
+    (printf "  ~a samples\n" (length c))
+    (newline)))
+
+;; Unrolls the stack until it hits a function on the negative side of the
+;; contract boundary (based on module location info).
+;; Will give bogus results if source location info is incomplete.
+(define (sample-prune-stack-trace sample)
+  (match-define (list blame thread-id timestamp stack-trace ...) sample)
+  (define caller-module (blame-negative blame))
+  (define new-stack-trace
+    (dropf stack-trace
+           (match-lambda
+            [(cons name loc)
+             (or (not loc)
+                 (not (equal? (srcloc-source loc) caller-module)))])))
+  (list* blame thread-id timestamp new-stack-trace))
+
+
+(provide (rename-out [contract-profile/user contract-profile]))
+
+;; TODO have kw args for profiler, etc.
+;; TODO have kw args for output files
+(define-syntax-rule (contract-profile/user body ...)
+  (let ([sampler (create-sampler (current-thread) 0.005 (current-custodian)
+                                 (list contract-continuation-mark-key))])
+    body ...
+    (sampler 'stop)
+    (define samples          (sampler 'get-snapshots))
+    (define contract-samples (for/list ([s (in-list (sampler 'get-custom-snapshots))])
+                               (and s (vector-ref s 0))))
+    (analyze-contract-samples contract-samples samples)))