1 (in-package :sb-cpu-affinity
)
5 ;; This is defined as a #DEFINE constant, but the .so stuff the value
6 ;; into a variable for us.
7 (eval-when (:compile-toplevel
:load-toplevel
)
8 (define-alien-variable cpu-setsize int
))
10 ;; This is sizeof(cpu_set_t)
11 (define-alien-variable cpu-mask-size int
)
13 ;; These are convenience wrappers around sched_set/getaffinity.
14 (define-alien-routine ("get_cpu_affinity_mask" %get-cpu-affinity-mask
) int
15 (mask (* (unsigned 8))))
16 (define-alien-routine ("set_cpu_affinity_mask" %set-cpu-affinity-mask
) int
17 (mask (* (unsigned 8))))
19 ;; These are wrappers around libc macros that manipulate the mask. Why
20 ;; the hell can't C people provide functions in addition to macros
21 ;; like this? Or just use inline functions?
22 (define-alien-routine zero-cpu-affinity-mask void
23 (mask (* (unsigned 8))))
24 (define-alien-routine ("cpu_affinity_p" %cpu-affinity-p
) int
26 (mask (* (unsigned 8))))
27 (define-alien-routine set-cpu-affinity void
29 (mask (* (unsigned 8))))
30 (define-alien-routine clear-cpu-affinity void
32 (mask (* (unsigned 8))))
34 ;;;; Nice lispy interface
36 (defconstant +cpu-limit
+ cpu-setsize
37 "Upper exclusive limit on the number of CPUs. Based on CPU_SETSIZE
40 (defvar *cpu-count
* nil
)
42 (defun forget-cpu-count ()
43 (setf *cpu-count
* nil
))
45 (pushnew 'forget-cpu-count sb-ext
:*save-hooks
*)
48 "Number of CPUs available in the system. Based on /proc/cpuinfo."
51 (let* ((key "processor")
53 (with-open-file (f "/proc/cpuinfo")
54 (loop for line
= (read-line f nil nil
)
56 count
(when (> (length line
) len
)
57 (string= key line
:end2 len
))))))))
59 (defstruct cpu-affinity-mask
63 (defmethod print-object ((mask cpu-affinity-mask
) stream
)
64 (print-unreadable-object (mask stream
:type t
)
65 ;; Print the locally interesting part of the mask.
66 (dotimes (i (cpu-count))
67 (if (cpu-affinity-p i mask
)
68 (write-char #\
1 stream
)
69 (write-char #\
0 stream
)))))
71 (defun make-cpu-mask ()
72 (make-alien (unsigned 8) cpu-mask-size
))
74 (defun get-cpu-affinity-mask ()
75 "Returns the CPU affinity mask of the current thread. The mask can
76 be inspected and mutated using CPU-AFFINITY-P, \(SETF CPU-AFFINITY-P),
77 and CLEAR-CPU-AFFINITY-MASK. To make any changes take effect, the mask
78 must be saved using SET-CPU-AFFINITY-MASK.
80 Using WITH-CPU-AFFINITY-MASK instead is recommended."
81 ;; FIXME: Malloc'ed mask is nasty, but libc doesn't seem to like
82 ;; stack allocated ones, nor does it seem to like freeing masks that
83 ;; have been used. So we never do. Gah.
84 (let ((mask (make-cpu-mask)))
85 (unless (zerop (%get-cpu-affinity-mask mask
))
86 (error "Could not read CPU affinity mask: ~A" (sb-int:strerror
)))
87 (make-cpu-affinity-mask :%mask mask
)))
89 (defun set-cpu-affinity-mask (mask)
90 "Sets the CPU affinity mask for the current thread.
92 Using WITH-CPU-AFFINITY-MASK :SAVE T instead is recommended."
93 (unless (zerop (%set-cpu-affinity-mask
(cpu-affinity-mask-%mask mask
)))
94 (error "Coud not write CPU affinity mask: ~A" (sb-int:strerror
))))
96 (defun cpu-affinity-p (cpu mask
)
97 "Returns T if the CPU \(a numeric indentifier between 0 and
98 +CPU-LIMIT+) is part of the MASK."
99 (plusp (%cpu-affinity-p cpu
(cpu-affinity-mask-%mask mask
))))
101 (defun (setf cpu-affinity-p
) (bool cpu mask
)
102 "Toggles presence of the CPU \(a numeric identifier between 0 and +CPU-LIMIT+)
104 (let ((%mask
(cpu-affinity-mask-%mask mask
)))
106 (set-cpu-affinity cpu %mask
)
107 (clear-cpu-affinity cpu %mask
)))
110 (defun clear-cpu-affinity-mask (mask)
111 "Removes all CPUs from the MASK."
112 (zero-cpu-affinity-mask (cpu-affinity-mask-%mask mask
))
115 (defmacro with-cpu-affinity-mask
((mask &key save
) &body body
)
116 "Reads the CPU affinity mask of the the current thread and binds it
117 to MASK. The mask can be inspected and mutated using CPU-AFFINITY-P,
118 \(SETF CPU-AFFINITY-P, and CLEAR-CPU-AFFINITY-MASK. Any changes take
119 effect only if SAVE is true (default is NIL)."
120 (let ((ok-n (gensym "OK")))
124 (setf ,mask
(get-cpu-affinity-mask))
125 (multiple-value-prog1 (progn ,@body
)
127 (when (and ,ok-n
,save
)
128 (set-cpu-affinity-mask ,mask
))))))
134 (with-cpu-affinity-mask (mask)
137 (with-cpu-affinity-mask (mask :save t
)
139 (clear-cpu-affinity-mask mask
)
141 (setf (cpu-affinity-p 0 mask
) t
))
143 (with-cpu-affinity-mask (mask)
146 (with-cpu-affinity-mask (mask :save t
)
147 ;; Only odd CPUs in mask.
148 (dotimes (cpu (cpu-count))
149 (setf (cpu-affinity-p cpu mask
) (oddp cpu
))))
151 (with-cpu-affinity-mask (mask)