X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Flate-extensions.lisp;h=48ee19018a5a4bb5293aed29a97caf77fa574ac0;hb=4f4906712a4fa98880fb0f8f036ca2add541b8a1;hp=77582d003ef3d028a206c8e30abcc7795ca61c21;hpb=ba3bf8ccc42770b90765cd839c6579e62b495bbb;p=sbcl.git diff --git a/src/code/late-extensions.lisp b/src/code/late-extensions.lisp index 77582d0..48ee190 100644 --- a/src/code/late-extensions.lisp +++ b/src/code/late-extensions.lisp @@ -73,99 +73,7 @@ sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag))))))) -(defmacro compare-and-swap (place old new &environment env) - "Atomically stores NEW in PLACE if OLD matches the current value of PLACE. -Two values are considered to match if they are EQ. Returns the previous value -of PLACE: if the returned value is EQ to OLD, the swap was carried out. - -PLACE must be an accessor form whose CAR is one of the following: - - CAR, CDR, FIRST, REST, SYMBOL-PLIST, SYMBOL-VALUE, SVREF - -or the name of a DEFSTRUCT created accessor for a slot whose declared type is -either FIXNUM or T. Results are unspecified if the slot has a declared type -other then FIXNUM or T. - -EXPERIMENTAL: Interface subject to change." - (flet ((invalid-place () - (error "Invalid first argument to COMPARE-AND-SWAP: ~S" place))) - (unless (consp place) - (invalid-place)) - ;; FIXME: Not the nicest way to do this... - (destructuring-bind (op &rest args) place - (case op - ((car first) - `(%compare-and-swap-car (the cons ,@args) ,old ,new)) - ((cdr rest) - `(%compare-and-swap-cdr (the cons ,@args) ,old ,new)) - (symbol-plist - `(%compare-and-swap-symbol-plist (the symbol ,@args) ,old (the list ,new))) - (symbol-value - (destructuring-bind (name) args - (flet ((slow (symbol) - (with-unique-names (n-symbol n-old n-new) - `(let ((,n-symbol ,symbol) - (,n-old ,old) - (,n-new ,new)) - (declare (symbol ,n-symbol)) - (about-to-modify-symbol-value ,n-symbol 'compare-and-swap ,n-new) - (%compare-and-swap-symbol-value ,n-symbol ,n-old ,n-new))))) - (if (sb!xc:constantp name env) - (let ((cname (constant-form-value name env))) - (if (eq :special (info :variable :kind cname)) - ;; Since we know the symbol is a special, we can just generate - ;; the type check. - `(%compare-and-swap-symbol-value - ',cname ,old (the ,(info :variable :type cname) ,new)) - (slow (list 'quote cname)))) - (slow name))))) - (svref - (let ((vector (car args)) - (index (cadr args))) - (unless (and vector index (not (cddr args))) - (invalid-place)) - (with-unique-names (v) - `(let ((,v ,vector)) - (declare (simple-vector ,v)) - (%compare-and-swap-svref ,v (%check-bound ,v (length ,v) ,index) ,old ,new))))) - (t - (let ((dd (info :function :structure-accessor op))) - (if dd - (let* ((structure (dd-name dd)) - (slotd (find op (dd-slots dd) :key #'dsd-accessor-name)) - (index (dsd-index slotd)) - (type (dsd-type slotd))) - (unless (eq t (dsd-raw-type slotd)) - (error "Cannot use COMPARE-AND-SWAP with structure accessor for a typed slot: ~S" - place)) - (when (dsd-read-only slotd) - (error "Cannot use COMPARE-AND-SWAP with structure accessor for a read-only slot: ~S" - place)) - `(truly-the (values ,type &optional) - (%compare-and-swap-instance-ref (the ,structure ,@args) - ,index - (the ,type ,old) (the ,type ,new)))) - (error "Invalid first argument to COMPARE-AND-SWAP: ~S" place)))))))) - -(macrolet ((def (name lambda-list ref &optional set) - #!+compare-and-swap-vops - (declare (ignore ref set)) - `(defun ,name (,@lambda-list old new) - #!+compare-and-swap-vops - (,name ,@lambda-list old new) - #!-compare-and-swap-vops - (let ((current (,ref ,@lambda-list))) - (when (eq current old) - ,(if set - `(,set ,@lambda-list new) - `(setf (,ref ,@lambda-list) new))) - current)))) - (def %compare-and-swap-car (cons) car) - (def %compare-and-swap-cdr (cons) cdr) - (def %compare-and-swap-instance-ref (instance index) %instance-ref %instance-set) - (def %compare-and-swap-symbol-plist (symbol) symbol-plist) - (def %compare-and-swap-symbol-value (symbol) symbol-value) - (def %compare-and-swap-svref (vector index) svref)) +;;;; ATOMIC-INCF and ATOMIC-DECF (defun expand-atomic-frob (name place diff) (flet ((invalid-place () @@ -177,7 +85,7 @@ EXPERIMENTAL: Interface subject to change." (aref (when (cddr args) (invalid-place)) - #!+(or) + #!+(or x86 x86-64 ppc) (with-unique-names (array) `(let ((,array (the (simple-array sb!ext:word (*)) ,(car args)))) (%array-atomic-incf/word @@ -189,7 +97,7 @@ EXPERIMENTAL: Interface subject to change." `(the sb!vm:signed-word ,diff)) (atomic-decf `(- (the sb!vm:signed-word ,diff)))))))) - #!-(or) + #!-(or x86 x86-64 ppc) (with-unique-names (array index old-value) (let ((incremented-value (ecase name @@ -289,13 +197,18 @@ EXPERIMENTAL: Interface subject to change." (expand-atomic-frob 'atomic-decf place diff)) ;; Interpreter stubs for ATOMIC-INCF. -#!+(or) +#!+(or x86 x86-64 ppc) (defun %array-atomic-incf/word (array index diff) (declare (type (simple-array word (*)) array) (fixnum index) (type sb!vm:signed-word diff)) (%array-atomic-incf/word array index diff)) +(defun spin-loop-hint () + #!+sb-doc + "Hints the processor that the current thread is spin-looping." + (spin-loop-hint)) + (defun call-hooks (kind hooks &key (on-error :error)) (dolist (hook hooks) (handler-case @@ -344,3 +257,182 @@ See also the declarations SB-EXT:GLOBAL and SB-EXT:ALWAYS-BOUND." (sb!c:with-source-location (source-location) (setf (info :source-location :variable name) source-location)) name) + +;;;; WAIT-FOR -- waiting on arbitrary conditions + +(defun %%wait-for (test stop-sec stop-usec) + (declare (function test)) + (labels ((try () + (declare (optimize (safety 0))) + (awhen (funcall test) + (return-from %%wait-for it))) + (tick (sec usec) + (declare (fixnum sec usec)) + ;; TICK is microseconds + (+ usec (* 1000000 sec))) + (get-tick () + (multiple-value-call #'tick + (decode-internal-time (get-internal-real-time))))) + (let* ((timeout-tick (when stop-sec (tick stop-sec stop-usec))) + (start (get-tick)) + ;; Rough estimate of how long a single attempt takes. + (try-ticks (progn + (try) (try) (try) + (max 1 (truncate (- (get-tick) start) 3))))) + ;; Scale sleeping between attempts: + ;; + ;; Start by sleeping for as many ticks as an average attempt + ;; takes, then doubling for each attempt. + ;; + ;; Max out at 0.1 seconds, or the 2 x time of a single try, + ;; whichever is longer -- with a hard cap of 10 seconds. + ;; + ;; FIXME: Maybe the API should have a :MAX-SLEEP argument? + (loop with max-ticks = (max 100000 (min (* 2 try-ticks) + (expt 10 7))) + for scale of-type fixnum = 1 + then (let ((x (logand most-positive-fixnum (* 2 scale)))) + (if (> scale x) + most-positive-fixnum + x)) + do (try) + (let* ((now (get-tick)) + (sleep-ticks (min (* try-ticks scale) max-ticks)) + (sleep + (if timeout-tick + ;; If sleep would take us past the + ;; timeout, shorten it so it's just + ;; right. + (if (>= (+ now sleep-ticks) timeout-tick) + (- timeout-tick now) + sleep-ticks) + sleep-ticks))) + (declare (fixnum sleep)) + (cond ((plusp sleep) + ;; microseconds to seconds and nanoseconds + (multiple-value-bind (sec nsec) + (truncate (* 1000 sleep) (expt 10 9)) + (with-interrupts + (sb!unix:nanosleep sec nsec)))) + (t + (return-from %%wait-for nil)))))))) + +(defun %wait-for (test timeout) + (declare (function test)) + (tagbody + :restart + (multiple-value-bind (to-sec to-usec stop-sec stop-usec deadlinep) + (decode-timeout timeout) + (declare (ignore to-sec to-usec)) + (return-from %wait-for + (or (%%wait-for test stop-sec stop-usec) + (when deadlinep + (signal-deadline) + (go :restart))))))) + +(defmacro wait-for (test-form &key timeout) + #!+sb-doc + "Wait until TEST-FORM evaluates to true, then return its primary value. +If TIMEOUT is provided, waits at most approximately TIMEOUT seconds before +returning NIL. + +If WITH-DEADLINE has been used to provide a global deadline, signals a +DEADLINE-TIMEOUT if TEST-FORM doesn't evaluate to true before the +deadline. + +Experimental: subject to change without prior notice." + `(dx-flet ((wait-for-test () (progn ,test-form))) + (%wait-for #'wait-for-test ,timeout))) + +(defmacro with-progressive-timeout ((name &key seconds) + &body body) + #!+sb-doc + "Binds NAME as a local function for BODY. Each time #'NAME is called, it +returns SECONDS minus the time that has elapsed since BODY was entered, or +zero if more time than SECONDS has elapsed. If SECONDS is NIL, #'NAME +returns NIL each time." + (with-unique-names (deadline time-left sec) + `(let* ((,sec ,seconds) + (,deadline + (when ,sec + (+ (get-internal-real-time) + (round (* ,seconds internal-time-units-per-second)))))) + (flet ((,name () + (when ,deadline + (let ((,time-left (- ,deadline (get-internal-real-time)))) + (if (plusp ,time-left) + (* (coerce ,time-left 'single-float) + ,(/ 1.0 internal-time-units-per-second)) + 0))))) + ,@body)))) + +(defmacro atomic-update (place update-fn &rest arguments &environment env) + #!+sb-doc + "Updates PLACE atomically to the value returned by calling function +designated by UPDATE-FN with ARGUMENTS and the previous value of PLACE. + +PLACE may be read and UPDATE-FN evaluated and called multiple times before the +update succeeds: atomicity in this context means that value of place did not +change between the time it was read, and the time it was replaced with the +computed value. + +PLACE can be any place supported by SB-EXT:COMPARE-AND-SWAP. + +Examples: + + ;;; Conses T to the head of FOO-LIST. + (defstruct foo list) + (defvar *foo* (make-foo)) + (atomic-update (foo-list *foo*) #'cons t) + + (let ((x (cons :count 0))) + (mapc #'sb-thread:join-thread + (loop repeat 1000 + collect (sb-thread:make-thread + (lambda () + (loop repeat 1000 + do (atomic-update (cdr x) #'1+) + (sleep 0.00001)))))) + ;; Guaranteed to be (:COUNT . 1000000) -- if you replace + ;; atomic update with (INCF (CDR X)) above, the result becomes + ;; unpredictable. + x) +" + (multiple-value-bind (vars vals old new cas-form read-form) + (get-cas-expansion place env) + `(let* (,@(mapcar 'list vars vals) + (,old ,read-form)) + (loop for ,new = (funcall ,update-fn ,@arguments ,old) + until (eq ,old (setf ,old ,cas-form)) + finally (return ,new))))) + +(defmacro atomic-push (obj place &environment env) + #!+sb-doc + "Like PUSH, but atomic. PLACE may be read multiple times before +the operation completes -- the write does not occur until such time +that no other thread modified PLACE between the read and the write. + +Works on all CASable places." + (multiple-value-bind (vars vals old new cas-form read-form) + (get-cas-expansion place env) + `(let* (,@(mapcar 'list vars vals) + (,old ,read-form) + (,new (cons ,obj ,old))) + (loop until (eq ,old (setf ,old ,cas-form)) + do (setf (cdr ,new) ,old) + finally (return ,new))))) + +(defmacro atomic-pop (place &environment env) + #!+sb-doc + "Like POP, but atomic. PLACE may be read multiple times before +the operation completes -- the write does not occur until such time +that no other thread modified PLACE between the read and the write. + +Works on all CASable places." + (multiple-value-bind (vars vals old new cas-form read-form) + (get-cas-expansion place env) + `(let* (,@(mapcar 'list vars vals)) + (loop for ,old = ,read-form + for ,new = (cdr ,old) + until (eq ,old (setf ,old ,cas-form)) + finally (return (car ,old))))))