Date: Wed, 02 Apr 2003 15:31:14 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Peter Wemm <peter@wemm.org> Cc: current@FreeBSD.org Subject: Re: libthr and 1:1 threading. Message-ID: <3E8B72C2.343AAEBD@mindspring.com> References: <20030402205608.2FCF82A8A5@canning.wemm.org>
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Peter Wemm wrote: > No. It gives the ability for a thread to block on a syscall without > stalling the entire system. Just try using mysqld on a system using libc_r > and heavy disk IO. You can't select() on a read() from disk. Thats the > ultimate reason to do it. The SMP parallelism is a bonus. Bug in FreeBSD's NBIO implementation. A read() that would result in page-in needs to queue the request, but return EAGAIN to user space to indicate the request cannot be satisfied. Making select() come true for disk I/O after the fault is satisfied is a seperate issue. Probably need to pass the fd all the way down. -- Terry
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