Date: Fri, 13 Nov 2009 07:09:12 +1100 (EST) From: Bruce Evans <brde@optusnet.com.au> To: "M. Warner Losh" <imp@bsdimp.com> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, delphij@FreeBSD.org, brde@optusnet.com.au Subject: Re: svn commit: r198848 - head/bin/ps Message-ID: <20091113065648.K2448@besplex.bde.org> In-Reply-To: <20091112.110732.1938114630.imp@bsdimp.com> References: <200911030928.nA39SjLx085597@svn.freebsd.org> <20091103214231.H23957@delplex.bde.org> <20091112.110732.1938114630.imp@bsdimp.com>
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On Thu, 12 Nov 2009, M. Warner Losh wrote: > I'd argue that as we get more and more cores that %CPU will need to > change. > > If we change it like Bruce suggests, then when we have 1024 > core/thread processors the 'pegged' thread shows up as 0.09% of the > CPU and likely nothing else shows up at all since the usages are > diluted by a factor of 1024. You mean, like I said not to. > However, for the 'TOP' display, 102400% of the CPU seems like a crazy > thing to report, even if it is consistent with what other systems > report for fewer cores going back to 1980's when VMS reported up to > 200% CPU for the VAX 11/785 on both BSD and VMS. 102400 isn't a very large number. 1M CPUs would give a more interesting number. Anyway, displaying %CPUs is the least of the problems in displaying many threads in top. top has the same problems as systat -p, but more so. It wants to display the top active threads, while systat -p only wants to display the top active threads if they are active enough to be considered pigs. You need the 6 metre high terminal to display the 1024 idle threads for top -SH. If you only want to display user threads then you will still need O(ncpu) lines to display enough active ones if all of the CPUs are actually used. > Likewise, we have issues with our current TOP display eating up a > bunch of columns for 55670k of core when 56M would generally give the > same info to the user (I say generally, because the former is useful > in watching for memory leaks). > > Maybe we just need to have top offer different views into this data > for the different needs that people have for it. A 'detailed' view > that helps expose even small differences that is useful in > development, and a 'condensed' version that gives more of the general > sense of what's going on in the system in a more concise format, but > might lack some of the details found today. > > Here's where my bikeshed proximity detector starts beeping... Adding all the different views would take a lot of paint and many would not like its color. I just want to avoid changing the standard view to one that works worse for small configurations. Bruce
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