From owner-freebsd-current  Thu Jul 26  2:22:58 2001
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Date: Wed, 25 Jul 2001 14:12:06 +0300
From: Maxim Sobolev <sobomax@FreeBSD.org>
Organization: Vega International Capital
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To: current@FreeBSD.org
Cc: Julian Elischer <julian@elischer.org>, stable@FreeBSD.org
Subject: Strange select(2) misbehaviour when linked with -pthread
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Hi,

I found that the attached small program behaves very strangely when
linked with -pthread - it chews 100% CPU cycles while waiting in
select(2). This misbehaviour observed both on 5-CURRENT and 4-STABLE
systems. *weird*

-Maxim
P.S. And yes, I know that I ought to use NULL instead of &tv when I
want to wait indefinitely in select(2), but it is how some programs
work.

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 name="selectbug.c"
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 filename="selectbug.c"

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>

int main()
{
	int retval, fd;
	u_int32_t timeout;
	struct timeval tv;
	fd_set mask;

	fd = 0;
	timeout = ~0;
	tv.tv_sec = timeout/1000;
	tv.tv_usec = (timeout%1000)*1000;
	FD_ZERO(&mask);
	FD_SET(fd, &mask);

	retval = select(1, &mask, NULL, NULL, &tv);
	exit(0);
}

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