Date: Fri, 11 Apr 2003 08:56:30 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Peter Jeremy <peterjeremy@optushome.com.au> Cc: freebsd-hackers@freebsd.org Subject: Re: Solaris 2.x compat. system accounting, sarcheck for fbsd(commercial) Message-ID: <3E96E5AE.548EBC6@mindspring.com> References: <20030411060823.GA27575@titan.klemm.apsfilter.org> <20030411080102.GC47320@cirb503493.alcatel.com.au>
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Peter Jeremy wrote: > On Fri, Apr 11, 2003 at 08:08:23AM +0200, Andreas Klemm wrote: > >I wrote some performance monitoring utilities and need for > >example a parameter wait for I/O, that I didn't find in our > >tools, did I overlook something ? > > "wait for I/O" is a System-V state that BSD doesn't measure. > One of the grey[er] beards may be able to answer why SysV does > and BSD doesn't consider "wait for I/O" a state worth measuring. It is a state equal to "idle", with I/O requests pending completion. The intent is to say "I would be running some process X, but I'm idle because I'm waiting for I/O". Part of the problem in reporting this in FreeBSD is the inability to attribute pending I/O requests e.g. as the result of a fault by a process or as a result of a fault by the kernel itself. This is an artifact of the unified VM and buffer cache. -- Terry
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