X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcode%2Funix.lisp;h=4c2bc79d324dfbcb6ffd18e86b6a03d91b8097bd;hb=f2847d6ed16e60390d000410d36ec7fb2570cdaf;hp=51477263b227a069c201c82b8e8c32adf9a1a3a3;hpb=4c84f2e80a87643acf19fa315c84fcd21f60b14d;p=sbcl.git diff --git a/src/code/unix.lisp b/src/code/unix.lisp index 5147726..4c2bc79 100644 --- a/src/code/unix.lisp +++ b/src/code/unix.lisp @@ -286,7 +286,6 @@ SYSCALL-FORM. Repeat evaluation of SYSCALL-FORM if it is interrupted." (defun unix-read (fd buf len) (declare (type unix-fd fd) (type (unsigned-byte 32) len)) - (int-syscall ("read" int (* char) int) fd buf len)) ;;; UNIX-WRITE accepts a file descriptor, a buffer, an offset, and the @@ -300,6 +299,10 @@ SYSCALL-FORM. Repeat evaluation of SYSCALL-FORM if it is interrupted." fd (with-alien ((ptr (* char) (etypecase buf ((simple-array * (*)) + ;; This SAP-taking is + ;; safe as BUF remains + ;; either in a register + ;; or on stack. (vector-sap buf)) (system-area-pointer buf)))) @@ -530,29 +533,52 @@ SYSCALL-FORM. Repeat evaluation of SYSCALL-FORM if it is interrupted." ;;;; sys/select.h +(defvar *on-dangerous-select* :warn) + +;;; Calling select in a bad place can hang in a nasty manner, so it's better +;;; to have some way to detect these. +(defun note-dangerous-select () + (let ((action *on-dangerous-select*) + (*on-dangerous-select* nil)) + (case action + (:warn + (warn "Starting a select without a timeout while interrupts are ~ + disabled.")) + (:error + (error "Starting a select without a timeout while interrupts are ~ + disabled.")) + (:backtrace + (write-line + "=== Starting a select without a timeout while interrupts are disabled. ===" + *debug-io*) + (sb!debug:backtrace))) + nil)) + ;;;; FIXME: Why have both UNIX-SELECT and UNIX-FAST-SELECT? ;;; Perform the UNIX select(2) system call. -(declaim (inline unix-fast-select)) ; (used to be a macro in CMU CL) +(declaim (inline unix-fast-select)) (defun unix-fast-select (num-descriptors read-fds write-fds exception-fds - timeout-secs &optional (timeout-usecs 0)) + timeout-secs timeout-usecs) (declare (type (integer 0 #.fd-setsize) num-descriptors) (type (or (alien (* (struct fd-set))) null) read-fds write-fds exception-fds) - (type (or null (unsigned-byte 31)) timeout-secs) - (type (unsigned-byte 31) timeout-usecs)) - ;; FIXME: CMU CL had - ;; (declare (optimize (speed 3) (safety 0) (inhibit-warnings 3))) - ;; here. Is that important for SBCL? If so, why? Profiling might tell us.. - (with-alien ((tv (struct timeval))) - (when timeout-secs - (setf (slot tv 'tv-sec) timeout-secs) - (setf (slot tv 'tv-usec) timeout-usecs)) - (int-syscall ("select" int (* (struct fd-set)) (* (struct fd-set)) - (* (struct fd-set)) (* (struct timeval))) - num-descriptors read-fds write-fds exception-fds - (if timeout-secs (alien-sap (addr tv)) (int-sap 0))))) + (type (or null (unsigned-byte 31)) timeout-secs timeout-usecs)) + (flet ((select (tv-sap) + (int-syscall ("select" int (* (struct fd-set)) (* (struct fd-set)) + (* (struct fd-set)) (* (struct timeval))) + num-descriptors read-fds write-fds exception-fds + tv-sap))) + (cond ((or timeout-secs timeout-usecs) + (with-alien ((tv (struct timeval))) + (setf (slot tv 'tv-sec) (or timeout-secs 0)) + (setf (slot tv 'tv-usec) (or timeout-usecs 0)) + (select (alien-sap (addr tv))))) + (t + (unless *interrupts-enabled* + (note-dangerous-select)) + (select (int-sap 0)))))) ;;; UNIX-SELECT accepts sets of file descriptors and waits for an event ;;; to happen on one of them or to time out. @@ -592,9 +618,11 @@ SYSCALL-FORM. Repeat evaluation of SYSCALL-FORM if it is interrupted." (rdf (struct fd-set)) (wrf (struct fd-set)) (xpf (struct fd-set))) - (when to-secs - (setf (slot tv 'tv-sec) to-secs) - (setf (slot tv 'tv-usec) to-usecs)) + (cond (to-secs + (setf (slot tv 'tv-sec) to-secs + (slot tv 'tv-usec) to-usecs)) + ((not *interrupts-enabled*) + (note-dangerous-select))) (num-to-fd-set rdf rdfds) (num-to-fd-set wrf wrfds) (num-to-fd-set xpf xpfds) @@ -603,7 +631,7 @@ SYSCALL-FORM. Repeat evaluation of SYSCALL-FORM if it is interrupted." (int-sap 0) (alien-sap (addr ,alienvar))))) (syscall ("select" int (* (struct fd-set)) (* (struct fd-set)) - (* (struct fd-set)) (* (struct timeval))) + (* (struct fd-set)) (* (struct timeval))) (values result (fd-set-to-num nfds rdf) (fd-set-to-num nfds wrf) @@ -959,22 +987,63 @@ SYSCALL-FORM. Repeat evaluation of SYSCALL-FORM if it is interrupted." (return pathname) (push pathname previous-pathnames)))) + +(defconstant micro-seconds-per-internal-time-unit + (/ 1000000 sb!xc:internal-time-units-per-second)) + ;;; UNIX specific code, that has been cleanly separated from the ;;; Windows build. #!-win32 (progn - (defconstant micro-seconds-per-internal-time-unit - (/ 1000000 sb!xc:internal-time-units-per-second)) - - (declaim (inline system-internal-real-time system-internal-run-time)) - (defun system-internal-real-time () - (multiple-value-bind (ignore seconds useconds) (unix-gettimeofday) - (declare (ignore ignore) (type (unsigned-byte 32) seconds useconds)) - (let ((uint (truncate useconds - micro-seconds-per-internal-time-unit))) - (declare (type (unsigned-byte 32) uint)) - (+ (* seconds sb!xc:internal-time-units-per-second) - uint)))) + (declaim (inline system-internal-run-time + system-real-time-values)) + + (defun system-real-time-values () + (multiple-value-bind (_ sec usec) (unix-gettimeofday) + (declare (ignore _) (type (unsigned-byte 32) sec usec)) + (values sec (truncate usec micro-seconds-per-internal-time-unit)))) + + ;; There are two optimizations here that actually matter (on 32-bit + ;; systems): substract the epoch from seconds and milliseconds + ;; separately, as those should remain fixnums for the first 17 years + ;; or so of runtime. Also, avoid doing consing a new bignum if the + ;; result would be = to the last result given. + ;; + ;; Note: the next trick would be to spin a separate thread to update + ;; a global value once per internal tick, so each individual call to + ;; get-internal-real-time would be just a memory read... but that is + ;; probably best left for user-level code. ;) + ;; + ;; Thanks to James Anderson for the optimization hint. + ;; + ;; Yes, it is possible to a computation to be GET-INTERNAL-REAL-TIME + ;; bound. + ;; + ;; --NS 2007-04-05 + (let ((e-sec 0) + (e-msec 0) + (c-sec 0) + (c-msec 0) + (now 0)) + (declare (type (unsigned-byte 32) e-sec c-sec) + (type fixnum e-msec c-msec) + (type unsigned-byte now)) + (defun reinit-internal-real-time () + (setf (values e-sec e-msec) (system-real-time-values) + c-sec 0 + c-msec 0)) + ;; If two threads call this at the same time, we're still safe, I believe, + ;; as long as NOW is updated before either of C-MSEC or C-SEC. Same applies + ;; to interrupts. --NS + (defun get-internal-real-time () + (multiple-value-bind (sec msec) (system-real-time-values) + (unless (and (= msec c-msec) (= sec c-sec)) + (setf now (+ (* (- sec e-sec) + sb!xc:internal-time-units-per-second) + (- msec e-msec)) + c-msec msec + c-sec sec)) + now))) (defun system-internal-run-time () (multiple-value-bind (ignore utime-sec utime-usec stime-sec stime-usec)