Re: A simple request (was Re: boring BK stats)

Rogier Wolff
2002-10-11T14:02:59Z

On Fri, Oct 11, 2002 at 03:35:38PM +0200, Rogier Wolff wrote:
> On Thu, Oct 10, 2002 at 07:28:18AM -0700, Larry McVoy wrote:
> > > The laptop has 200MB RAM, and mozilla and a ton of xterms loaded. IDE
> > > drives w/ Intel PIIX4 controller. The Dual Athlon has 512MB RAM, and I
> > > forget what kind of IDE controller -- I think AMD. IDE drives as well.
> > >
> > > BitKeeper must scan the entire tree when doing a checkin or checkout, so
>
> [...]
>
> > In low memory situations you really want to run the tree compressed.
> > ON a fast machine do a "bk -r admin -Z" and then clone that onto your
> > laptop. I think that will drop the tree to about 145MB which will
> > help, maybe. I suspect that you use enough of the rest of your 200MB
> > that it still won't fit.
>
> [...]
> > There is only so much we can do when you are trying to cram 10 pounds of
> > crap in a 5 pound bag :(
>
> The reason that one or two years ago my "diff+multiple trees" beat
> bitkeeper on the performance front was that diff would only touch
> inode-metadata, and not the files themselves. You can cache the
> file-metadata (inodes) of a 200M tree in a couple of megabytes of RAM.

Jeff:

The trick is that I would have hardlinked trees. Thus

linux-2.2.18.clean/drivers/char/tty_ioctl.c
and
linux-2.2.18.rio/drivers/char/tty_ioctl.c

would have the same inode number, and diff wouldn't even bother to
open the file....

Roger.

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