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glibc renders random() thread-safe by wrapping a futex lock around it; testing reveals that this limits the performance of pgbench on machines with many CPU cores. Rather than switching to random_r(), which is only available on GNU systems and crashes unless you use undocumented alchemy to initialize the random state properly, switch to our built-in implementation of erand48(), which is both thread-safe and concurrent. Since the list of reasons not to use the operating system's erand48() is getting rather long, rename ours to pg_erand48() (and similarly for our implementations of lrand48() and srand48()) and just always use those. We were already doing this on Cygwin anyway, and the glibc implementation is not quite thread-safe, so pgbench wouldn't be able to use that either. Per discussion with Tom Lane.
26 lines
468 B
C
26 lines
468 B
C
/*-------------------------------------------------------------------------
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*
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* random.c
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* random() wrapper
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*
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* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/port/random.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "c.h"
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#include <math.h>
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long
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random()
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{
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return pg_lrand48();
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}
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