(package-hashtable-free table)
(package-hashtable-deleted table))))
-;;; the maximum density we allow in a package hashtable
-(defconstant package-rehash-threshold 0.75)
+;;; the maximum load factor we allow in a package hashtable
+(defconstant +package-rehash-threshold+ 0.75)
+
+;;; the load factor desired for a package hashtable when writing a
+;;; core image
+(defconstant +package-hashtable-image-load-factor+ 0.5)
;;; Make a package hashtable having a prime number of entries at least
-;;; as great as (/ SIZE PACKAGE-REHASH-THRESHOLD). If RES is supplied,
+;;; as great as (/ SIZE +PACKAGE-REHASH-THRESHOLD+). If RES is supplied,
;;; then it is destructively modified to produce the result. This is
;;; useful when changing the size, since there are many pointers to
;;; the hashtable.
+;;; Actually, the smallest table built here has three entries. This
+;;; is necessary because the double hashing step size is calculated
+;;; using a division by the table size minus two.
(defun make-or-remake-package-hashtable (size
&optional
res)
(flet ((actual-package-hashtable-size (size)
(loop for n of-type fixnum
- from (logior (truncate size package-rehash-threshold) 1)
+ from (logior (ceiling size +package-rehash-threshold+) 1)
by 2
when (positive-primep n) return n)))
(let* ((n (actual-package-hashtable-size size))
- (size (truncate (* n package-rehash-threshold)))
+ (size (truncate (* n +package-rehash-threshold+)))
(table (make-array n))
(hash (make-array n
:element-type '(unsigned-byte 8)
(package-hashtable-deleted res) 0)
(setf res (%make-package-hashtable table hash size)))
res)))
+
+;;; Destructively resize TABLE to have room for at least SIZE entries
+;;; and rehash its existing entries.
+(defun resize-package-hashtable (table size)
+ (let* ((vec (package-hashtable-table table))
+ (hash (package-hashtable-hash table))
+ (len (length vec)))
+ (make-or-remake-package-hashtable size table)
+ (dotimes (i len)
+ (when (> (aref hash i) 1)
+ (add-symbol table (svref vec i))))))
\f
;;;; package locking operations, built conditionally on :sb-package-locks
;;; Add a symbol to a package hashtable. The symbol is assumed
;;; not to be present.
(defun add-symbol (table symbol)
+ (when (zerop (package-hashtable-free table))
+ ;; The hashtable is full. Resize it to be able to hold twice the
+ ;; amount of symbols than it currently contains. The actual new size
+ ;; can be smaller than twice the current size if the table contained
+ ;; deleted entries.
+ (resize-package-hashtable table
+ (* (- (package-hashtable-size table)
+ (package-hashtable-deleted table))
+ 2)))
(let* ((vec (package-hashtable-table table))
(hash (package-hashtable-hash table))
(len (length vec))
(sxhash (%sxhash-simple-string (symbol-name symbol)))
- (h2 (the fixnum (1+ (the fixnum (rem sxhash
- (the fixnum (- len 2))))))))
- (declare (fixnum len sxhash h2))
- (cond ((zerop (the fixnum (package-hashtable-free table)))
- (make-or-remake-package-hashtable (* (package-hashtable-size table)
- 2)
- table)
- (add-symbol table symbol)
- (dotimes (i len)
- (declare (fixnum i))
- (when (> (the fixnum (aref hash i)) 1)
- (add-symbol table (svref vec i)))))
- (t
- (do ((i (rem sxhash len) (rem (+ i h2) len)))
- ((< (the fixnum (aref hash i)) 2)
- (if (zerop (the fixnum (aref hash i)))
- (decf (package-hashtable-free table))
- (decf (package-hashtable-deleted table)))
- (setf (svref vec i) symbol)
- (setf (aref hash i)
- (entry-hash (length (symbol-name symbol))
- sxhash)))
- (declare (fixnum i)))))))
+ (h2 (1+ (rem sxhash (- len 2)))))
+ (declare (fixnum sxhash h2))
+ (do ((i (rem sxhash len) (rem (+ i h2) len)))
+ ((< (the fixnum (aref hash i)) 2)
+ (if (zerop (the fixnum (aref hash i)))
+ (decf (package-hashtable-free table))
+ (decf (package-hashtable-deleted table)))
+ (setf (svref vec i) symbol)
+ (setf (aref hash i)
+ (entry-hash (length (symbol-name symbol))
+ sxhash)))
+ (declare (fixnum i)))))
+
+;;; Resize the package hashtables of all packages so that their load
+;;; factor is +PACKAGE-HASHTABLE-IMAGE-LOAD-FACTOR+. Called from
+;;; SAVE-LISP-AND-DIE to optimize space usage in the image.
+(defun tune-hashtable-sizes-of-all-packages ()
+ (flet ((tune-table-size (table)
+ (resize-package-hashtable
+ table
+ (round (* (/ +package-rehash-threshold+
+ +package-hashtable-image-load-factor+)
+ (- (package-hashtable-size table)
+ (package-hashtable-free table)
+ (package-hashtable-deleted table)))))))
+ (dolist (package (list-all-packages))
+ (tune-table-size (package-internal-symbols package))
+ (tune-table-size (package-external-symbols package)))))
;;; Find where the symbol named STRING is stored in TABLE. INDEX-VAR
;;; is bound to the index, or NIL if it is not present. SYMBOL-VAR
(with-symbol (index symbol table string length hash ehash)
(setf (aref (package-hashtable-hash table) index) 1)
(setf (aref (package-hashtable-table table) index) nil)
- (incf (package-hashtable-deleted table)))))
+ (incf (package-hashtable-deleted table))))
+ ;; If the table is less than one quarter full, halve its size and
+ ;; rehash the entries.
+ (let* ((size (package-hashtable-size table))
+ (deleted (package-hashtable-deleted table))
+ (used (- size
+ (package-hashtable-free table)
+ deleted)))
+ (declare (type fixnum size deleted used))
+ (when (< used (truncate size 4))
+ (resize-package-hashtable table (* used 2)))))
\f
;;; Enter any new NICKNAMES for PACKAGE into *PACKAGE-NAMES*.
;;; If there is a conflict then give the user a chance to do
(symbols (cdr cold-package-symbols-entry))
(shadows (package-shadowing-symbols cold-package))
(documentation (base-string-to-core (documentation cold-package t)))
+ (internal-count 0)
+ (external-count 0)
(internal *nil-descriptor*)
(external *nil-descriptor*)
(imported-internal *nil-descriptor*)
(case where
(:internal (if imported-p
(cold-push handle imported-internal)
- (cold-push handle internal)))
+ (progn
+ (cold-push handle internal)
+ (incf internal-count))))
(:external (if imported-p
(cold-push handle imported-external)
- (cold-push handle external)))))))
+ (progn
+ (cold-push handle external)
+ (incf external-count))))))))
(let ((r *nil-descriptor*))
(cold-push documentation r)
(cold-push shadowing r)
(cold-push imported-internal r)
(cold-push external r)
(cold-push internal r)
- (cold-push (make-make-package-args cold-package) r)
+ (cold-push (make-make-package-args cold-package
+ internal-count
+ external-count)
+ r)
;; FIXME: It would be more space-efficient to use vectors
;; instead of lists here, and space-efficiency here would be
;; nice, since it would reduce the peak memory usage in
(cold-set 'sb!vm::*fp-constant-0f0* (number-to-core 0f0))
(cold-set 'sb!vm::*fp-constant-1f0* (number-to-core 1f0))))
-;;; Make a cold list that can be used as the arg list to MAKE-PACKAGE in order
-;;; to make a package that is similar to PKG.
-(defun make-make-package-args (pkg)
+;;; Make a cold list that can be used as the arg list to MAKE-PACKAGE in
+;;; order to make a package that is similar to PKG.
+(defun make-make-package-args (pkg internal-count external-count)
(let* ((use *nil-descriptor*)
(cold-nicknames *nil-descriptor*)
(res *nil-descriptor*))
(dolist (warm-nickname warm-nicknames)
(cold-push (base-string-to-core warm-nickname) cold-nicknames)))
- (cold-push (number-to-core (truncate (package-internal-symbol-count pkg)
- 0.8))
- res)
+ ;; INTERNAL-COUNT and EXTERNAL-COUNT are the number of symbols that
+ ;; the package contains in the core. We arrange for the package
+ ;; symbol tables to be created somewhat larger so that they don't
+ ;; need to be rehashed so easily when additional symbols are
+ ;; interned during the warm build.
+ (cold-push (number-to-core (truncate internal-count 0.8)) res)
(cold-push (cold-intern :internal-symbols) res)
- (cold-push (number-to-core (truncate (package-external-symbol-count pkg)
- 0.8))
- res)
+ (cold-push (number-to-core (truncate external-count 0.8)) res)
(cold-push (cold-intern :external-symbols) res)
(cold-push cold-nicknames res)
projects / sbcl.git / commitdiff