40% slowdown with dynamic /bin/sh

Frank Mayhar frank at exit.com
Mon Nov 24 18:14:52 PST 2003

Daniel O'Connor wrote:
> You DO know FreeBSD is a cooperative project right?

Of course I do.  I was using it when it was just 386BSD 0.1 and a patchkit.
I've watched it through a lot of changes and while I've never been a part
of the team, mostly due to lack of time, I try to throw whatever I can at
it when I'm able.

On the _other_ hand:

> I hardly think you're in a position to complain about a (probably very minor) 
> performance loss which has a trivial work around, which also benefits a fair 
> number of users.

_This_ is the issue.  You assert that this change "benefits a fair number
of users."  I and others assert that it hurts performance and makes disaster
recovery more complex (while the existence of /rescue is a great idea, it
still adds complexity).  There's proof for our assertions, but all I'm
hearing from you guys is handwaving.

And I'm _not_ trying to be insulting or condescending.  I've done handwaving
myself in the past, but I try to be aware of it and only do it when I can
justify it.  In this case, the handwaving is in place of real evidence.
So, how much does it help?  How _many_ users will it benefit, in general?
Sure, it doesn't matter for a webserver that runs httpd or for a database
server that does nothing but run Postgresql, but those cases are irrelevant
to the issue of a dynamically-linked root.  They are affected neither way.
It is people who run a variety of applications that will be affected,
either good or bad.

So, we've seen data about the performance hit.  What about data about
improved performance or improved function in some other way?  What is
the compelling reason to move to a dynamic root?

So far I've seen no argument that was even convincing, let alone compelling.
Frank Mayhar frank at exit.com	http://www.exit.com/
Exit Consulting                 http://www.gpsclock.com/

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