Date: Sun, 6 Feb 2000 14:46:31 -0500 (EST) From: Zhihui Zhang <zzhang@cs.binghamton.edu> To: freebsd-hackers@freebsd.org, arla-drinkers@stacken.kth.se Subject: Writing a multithreaded daemon process Message-ID: <Pine.GSO.3.96.1000206142832.1751A-100000@sol.cs.binghamton.edu>
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After reading part of the Arla daemon code available at http://www.stacken.kth.se/projekt/arla/, I feel it is a real good design. The daemon code is a multi-threaded user process that does most of the job and the kernel is an interface to VFS. They communicate with each other via a character device. But I am wondering if the performance is good since you sometimes have to cross user-system boundary up to four times for a single read operations: read() --> Arla daemon --> network --> install data into kernel If the daemon can somehow reside entirely inside the kernel, like NFS daemon, we can save those crossings. But the daemon is a multi-threaded process and we have no kernel thread yet, so I do not know how to do better if possible. Maybe all user filesystems have to live with this limitation. Any help is appreciated. -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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