X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fpcl%2Fcache.lisp;h=bb148ffd4fee0457dfb9368b4d8b25458dccd4e5;hb=90c2b0563695904419451b6172efcf9c7008ad8b;hp=7985c5c3a42ef9c2129b79df2b0daa09581807fe;hpb=b6ed0e20d468099b62d27095db7d18f76d8886d2;p=sbcl.git diff --git a/src/pcl/cache.lisp b/src/pcl/cache.lisp index 7985c5c..bb148ff 100644 --- a/src/pcl/cache.lisp +++ b/src/pcl/cache.lisp @@ -81,13 +81,28 @@ ;; (mod index (length vector)) ;; using a bitmask. (vector #() :type simple-vector) - ;; The bitmask used to calculate (mod index (length vector))l + ;; The bitmask used to calculate (mod (* line-size line-hash) (length vector))). (mask 0 :type fixnum) ;; Current probe-depth needed in the cache. (depth 0 :type index) ;; Maximum allowed probe-depth before the cache needs to expand. (limit 0 :type index)) +(defun compute-cache-mask (vector-length line-size) + ;; Since both vector-length and line-size are powers of two, we + ;; can compute a bitmask such that + ;; + ;; (logand ) + ;; + ;; is "morally equal" to + ;; + ;; (mod (* ) ) + ;; + ;; This is it: (1- vector-length) is #b111... of the approriate size + ;; to get the MOD, and (- line-size) gives right the number of zero + ;; bits at the low end. + (logand (1- vector-length) (- line-size))) + ;;; The smallest power of two that is equal to or greater then X. (declaim (inline power-of-two-ceiling)) (defun power-of-two-ceiling (x) @@ -115,7 +130,7 @@ ;;; policy into account here (speed vs. space.) (declaim (inline compute-limit)) (defun compute-limit (size) - (ceiling (sqrt size) 2)) + (ceiling (sqrt (sqrt size)))) ;;; Returns VALUE if it is not ..EMPTY.., otherwise executes ELSE: (defmacro non-empty-or (value else) @@ -173,10 +188,11 @@ (defun compute-cache-index (cache layouts) (let ((index (hash-layout-or (car layouts) (return-from compute-cache-index nil)))) + (declare (fixnum index)) (dolist (layout (cdr layouts)) (mixf index (hash-layout-or layout (return-from compute-cache-index nil)))) ;; align with cache lines - (logand (* (cache-line-size cache) index) (cache-mask cache)))) + (logand index (cache-mask cache)))) ;;; Emit code that does lookup in cache bound to CACHE-VAR using ;;; layouts bound to LAYOUT-VARS. Go to MISS-TAG on event of a miss or @@ -192,17 +208,16 @@ (with-unique-names (n-index n-vector n-depth n-pointer n-mask MATCH-WRAPPERS EXIT-WITH-HIT) `(let* ((,n-index (hash-layout-or ,(car layout-vars) (go ,miss-tag))) - (,n-vector (cache-vector ,cache-var))) + (,n-vector (cache-vector ,cache-var)) + (,n-mask (cache-mask ,cache-var))) (declare (index ,n-index)) ,@(mapcar (lambda (layout-var) `(mixf ,n-index (hash-layout-or ,layout-var (go ,miss-tag)))) (cdr layout-vars)) ;; align with cache lines - (setf ,n-index (logand (the fixnum (* ,n-index ,line-size)) - (cache-mask ,cache-var))) + (setf ,n-index (logand ,n-index ,n-mask)) (let ((,n-depth (cache-depth ,cache-var)) - (,n-pointer ,n-index) - (,n-mask (cache-mask ,cache-var))) + (,n-pointer ,n-index)) (declare (index ,n-depth ,n-pointer)) (tagbody ,MATCH-WRAPPERS @@ -312,7 +327,7 @@ :line-size line-size :vector (make-array length :initial-element '..empty..) :value value - :mask (1- length) + :mask (compute-cache-mask length line-size) :limit (compute-limit adjusted-size)) ;; Make a smaller one, then (make-cache :key-count key-count :value value :size (ceiling size 2))))) @@ -328,7 +343,7 @@ :again (setf (cache-vector copy) (make-array length :initial-element '..empty..) (cache-depth copy) 0 - (cache-mask copy) (1- length) + (cache-mask copy) (compute-cache-mask length (cache-line-size cache)) (cache-limit copy) (compute-limit (/ length (cache-line-size cache)))) (map-cache (lambda (layouts value) (unless (try-update-cache copy layouts value) @@ -347,11 +362,30 @@ copy)) (defun cache-has-invalid-entries-p (cache) - (and (find-if (lambda (elt) - (and (typep elt 'layout) - (zerop (layout-clos-hash elt)))) - (cache-vector cache)) - t)) + (let ((vector (cache-vector cache)) + (line-size (cache-line-size cache)) + (key-count (cache-key-count cache)) + (mask (cache-mask cache)) + (index 0)) + (loop + ;; Check if the line is in use, and check validity of the keys. + (let ((key1 (svref vector index))) + (when (cache-key-p key1) + (if (zerop (layout-clos-hash key1)) + ;; First key invalid. + (return-from cache-has-invalid-entries-p t) + ;; Line is in use and the first key is valid: check the rest. + (loop for offset from 1 below key-count + do (let ((thing (svref vector (+ index offset)))) + (when (or (not (cache-key-p thing)) + (zerop (layout-clos-hash thing))) + ;; Incomplete line or invalid layout. + (return-from cache-has-invalid-entries-p t))))))) + ;; Line empty of valid, onwards. + (setf index (next-cache-index mask index line-size)) + (when (zerop index) + ;; wrapped around + (return-from cache-has-invalid-entries-p nil))))) (defun hash-table-to-cache (table &key value key-count) (let ((cache (make-cache :key-count key-count :value value @@ -417,8 +451,8 @@ (line-size (cache-line-size cache)) (key-count (cache-key-count cache)) (valuep (cache-value cache)) - (size (/ (length vector) line-size)) (mask (cache-mask cache)) + (size (/ (length vector) line-size)) (index 0) (elt nil) (depth 0)) @@ -453,5 +487,33 @@ :key-count (cache-key-count cache) :line-size line-size :value valuep - :mask (cache-mask cache) + :mask mask :limit (cache-limit cache)))) + +;;;; For debugging & collecting statistics. + +(defun map-all-caches (function) + (dolist (p (list-all-packages)) + (do-symbols (s p) + (when (eq p (symbol-package s)) + (dolist (name (list s + `(setf ,s) + (slot-reader-name s) + (slot-writer-name s) + (slot-boundp-name s))) + (when (fboundp name) + (let ((fun (fdefinition name))) + (when (typep fun 'generic-function) + (let ((cache (gf-dfun-cache fun))) + (when cache + (funcall function name cache))))))))))) + +(defun check-cache-consistency (cache) + (let ((table (make-hash-table :test 'equal))) + (map-cache (lambda (layouts value) + (declare (ignore value)) + (if (gethash layouts table) + (cerror "Check futher." + "Multiple appearances of ~S." layouts) + (setf (gethash layouts table) t))) + cache)))