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diff --git a/doc/ck_pr_stall b/doc/ck_pr_stall new file mode 100644 index 0000000..bc46647 --- /dev/null +++ b/doc/ck_pr_stall @@ -0,0 +1,86 @@ +.\" +.\" Copyright 2013 Samy Al Bahra. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" +.Dd April 7, 2013 +.Dt ck_pr_stall 3 +.Sh NAME +.Nm ck_pr_stall +.Nd busy-wait primitive +.Sh LIBRARY +Concurrency Kit (libck, \-lck) +.Sh SYNOPSIS +.In ck_pr.h +.Ft void +.Fn ck_pr_stall void +.Sh DESCRIPTION +The +.Fn ck_pr_stall 3 +function should be used inside retry paths of busy-wait loops. +It not only serves as a compiler barrier, but on some architectures +it emits cycle-saving instructions. +.Sh EXAMPLE +.Bd -literal -offset indent + +#include <ck_pr.h> + +static int ready = 0; + +void +function(void) +{ + + /* Busy-wait until ready is non-zero. */ + while (ck_pr_load_int(&ready) == 0) + ck_pr_stall(); + + return; +} +.Ed +.Sh SEE ALSO +.Xr ck_pr_fence_load 3 , +.Xr ck_pr_fence_load_depends 3 , +.Xr ck_pr_fence_store 3 , +.Xr ck_pr_fence_memory 3 , +.Xr ck_pr_barrier 3 , +.Xr ck_pr_fas 3 , +.Xr ck_pr_load 3 , +.Xr ck_pr_store 3 , +.Xr ck_pr_faa 3 , +.Xr ck_pr_inc 3 , +.Xr ck_pr_dec 3 , +.Xr ck_pr_neg 3 , +.Xr ck_pr_not 3 , +.Xr ck_pr_add 3 , +.Xr ck_pr_sub 3 , +.Xr ck_pr_and 3 , +.Xr ck_pr_or 3 , +.Xr ck_pr_xor 3 , +.Xr ck_pr_cas 3 , +.Xr ck_pr_btc 3 , +.Xr ck_pr_bts 3 , +.Xr ck_pr_btr 3 +.Pp +Additional information available at http://concurrencykit.org/ |