Date: Sun, 2 Dec 2001 13:20:01 -0500 From: Alan Eldridge <alane@geeksrus.net> To: freebsd-questions@freebsd.org Subject: parallel port i/o hogs cpu badly; is this normal? Message-ID: <20011202132001.A42382@wwweasel.geeksrus.net>
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I have an HP postsript laser (2100M) on a parallel intfc. [alane ~]$ uname -a FreeBSD wwweasel.geeksrus.net 4.4-RELEASE FreeBSD 4.4-RELEASE #0: Sun Oct 28 04:44:34 EST 2001 root@wwweasel.geeksrus.net:/usr/src-4.4-RELEASE/sys/compile/WWWEASEL i386 [alane ~]$ grep -i parallel /var/run/dmesg.boot ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0 When I print a document that is heavy in graphics, it's large. Multi-megabytes. That's expected 'cause postscript is verbose. But what surprises me is that copying that data to the parallel intfc burns up an incredible amount of CPU. Until the document is printed, there's a steady bg buzz of ~10% CPU use, with periods of 50% and even 100% CPU utilization by the 'parallel'[1] process. The load is sufficient that it locks out the mouse on X (interrupt blocking?). Anyone care to comment? Does this sound normal? Is there a way to reduce the amount of CPU needed to drive the parallel port? Notes: [1] /usr/local/libexec/cups/backend/parallel is the device interface using by the print/cups package. -- Alan Eldridge #include <cstdlib> free(sklyarov); To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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