Date: Mon, 27 Aug 2001 17:27:32 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Julian Elischer <julian@elischer.org> Cc: <current@FreeBSD.ORG> Subject: Re: KSE kernel comparissons Message-ID: <20010827170927.V23439-100000@besplex.bde.org> In-Reply-To: <3B896A82.DAAB4110@elischer.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, 26 Aug 2001, Julian Elischer wrote: > Comparative times for 'make buildworld' > for unmodified and KSE (milestone-2) kernels > > unmodified -current > 2138.464u 3358.378s 1:37:39.77 93.8% 842+1080k 45105+176988io 3208pf+0w > modified KSE kernel > 2143.716u 3363.311s 1:37:50.33 93.8% 841+1081k 45435+176988io 3214pf+0w > > I'm very glad to see that the overhead added was not too great. > (well within the margin of error I'm sure) Since it is non-negative, why would anyone want it? However, the benchmark seems to be flawed. Buildworld's system time should be only about 20% of its user time. To pessimize it by a factor of 7.5, you need to turn on lots of debugging options (which are on by default in -current). > More actual code will be needed to get away from 1:1, so this is just a > baseline. > > the next steps are for us a s a groupt to decide if this is really the way we > want to go, > and if so, whether we want to commit these changes to make them available for > the world > to work on as a base for real threading support. The alternative is to > do linux-type threading with processes (peter wemm has been investigating a > variant > on this scheme). This is probably a no-turning-back commit. How much faster (or slower) will it be for threaded programs (for various numbers of CPUs)? I don't see how it can be faster for a single CPU (interrupt threads in the kernel show that using threads tends to pessimize both efficiency and latency for a single CPU). Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010827170927.V23439-100000>