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On Wed, Apr 28, 2004 at 08:00:16AM +0900, enami tsugutomo wrote:
> > 2) In uvmhist, half of the string lengths are of the format strings. gc=
c=3D20
> > will turn strlen("Foo") into a constant (3 in this case) at compile tim=
e.=3D
> > =3D20
> > So by storing lengths, our compiler is removing half the calls to=3D20
> > strlen().
>=20
> Though it is easily fixable, that is not true with current
> implementation.

Huh? I was saying that we have two lengths we store in the uvmhist=20
entries, and that one of them is strlen()'s will be turned into a constant=
=20
at compile time by our compiler. How is that not true?

> > The uvm history system is designed to handle logging a very busy kernel=
=3D20
> > subsystem to disk very efficiently.
>=20
> What do you mean?  I don't think there is such feature (log to disk),
> except vmstat > file (and this is not always useful; with the first
> item below, it was useful to dump 30000 entries.  it was pain dumping
> those on serial console).

True. My first read of vmstat was wrong - I thought it would keep dumping.

> ...BTW, things I actually needed for uvmhist in the past are:
>=20
> - knob to stop logging.  this is to prevent the necessary log won't be
>   overwritten by others.

That would be a cool feature.

> - control how timestamp is calcurated; microtime is heavy for some
>   situation.

Sounds like a good compile option.

> - version of UVMHIST_CALLED() which doesn't call UVMHIST_LOG().
>   sometimes it was neccesary to log only on certian condition
>   (otherwise the log buffer is filled with `xxx called!').

Agreed. Sounds like another good compile option.

Take care,

Bill

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