40% slowdown with dynamic /bin/sh

Sam Leffler sam at errno.com
Mon Nov 24 21:19:32 PST 2003


On Monday 24 November 2003 07:06 pm, Andrew Gallatin wrote:
> M. Warner Losh writes:
>  > In message: <16322.47726.903593.393976 at grasshopper.cs.duke.edu>
>  > I'm just saying that most of the developers I'm talking to on IRC say
>  > this tread is insane, has no content and they are blowing it off
>  > because of that.  A concrete, real benchmark will go a long way
>  > towards changing that.  Until then, you are as good as kill filed.
>
> How about Gordon's initial bootstone, which increased by 25%?
> http://docs.freebsd.org/cgi/mid.cgi?16091.44150.539095.704531
>
> And I just did a "make clean" run in /usr/ports/archivers (by manually
> mv'ing a static and dynamic sh to /bin in turn):
>
> static:       96.63 real        53.45 user        39.27 sys
> dynamic:     112.42 real        55.51 user        51.62 sys
>
> The wall clock is bad (16% worse) and the system time is worse (31%).
>
>
> So..
>
> 1) Microbenchmark:	40% worse
> 2) Bootstone(*):	25% worse
> 3) Ports:		16% worse

I don't believe it was ever demonstrated there was no significant performance 
loss.  I think the switch should not be made until this is resolved.  netbsd 
went through this recently and made an effort to bring performance of a 
dynamic root in line with a static root before making the change.

	Sam



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