Date: Fri, 29 Apr 2005 15:26:34 +0400 From: "Andrew L. Neporada" <andr@dgap.mipt.ru> To: freebsd-hackers@freebsd.org Subject: open("/dev/cuaaX") is slow Message-ID: <20050429112634.GA63285@nas.dgap.mipt.ru>
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--W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, hackers! It seems that reopening /dev/cuaaX devices after close() takes exactly 3 seconds on FreeBSD 4.10 (sorry, I've no 5.x systems available at the moment). Here is output of attached program: open() time: 155 us open() time: 2995729 us open() time: 2999811 us open() time: 2999608 us open() time: 2999711 us open() time: 2999720 us open() time: 2999713 us open() time: 2999744 us open() time: 2999673 us open() time: 2999706 us Is this 3 second delay necessary? Can I get rid of it? Andrew. --W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="siotest.c" #include <sys/time.h> #include <stdio.h> #include <fcntl.h> int main(void) { int fd, i; long us; struct timeval tv1, tv2; for (i = 0; i < 10; i++) { gettimeofday(&tv1, NULL); fd = open("/dev/cuaa0", O_RDWR); gettimeofday(&tv2, NULL); us = (tv2.tv_sec - tv1.tv_sec) * 1000000 + (tv2.tv_usec - tv1.tv_usec); printf("open() time: %d us\n", us); if (fd == -1) { perror("open"); exit(1); } close(fd); } } --W/nzBZO5zC0uMSeA--
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