Re: Solved (Re: -current vs. -stable network performance)

2001-12-14 Thread David Malone

On Fri, Dec 14, 2001 at 03:16:57AM -0800, Luigi Rizzo wrote:
> > How about fixing it for real as described in the commit message?
> 
> The real fix, for me, is the one-line change to M_LEADINGSPACE.
> The one described in the commit message was just Bosko's point of
> view, with which I and many others disagree, and which requires an
> extensive scrutiny of the code and a change of the commonly understood
> semantics in M_LEADINGSPACE.

I think we should make this change for the moment as it doesn't
change the current meaning of M_LEADINGSPACE and seems to improve
performance a bit. Later, we can decide if changing the meaning of
M_LEADINGSPACE is a useful thing to do.

David.

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Re: Solved (Re: -current vs. -stable network performance)

2001-12-14 Thread Luigi Rizzo

On Fri, Dec 14, 2001 at 02:34:36AM -0800, Peter Wemm wrote:
> Luigi Rizzo wrote:
> [..]
> > The change below has been committed to STABLE 7 weeks ago, but did
> > not go into CURRENT because there was some disagreement on the
...
> Incidently, this is a poster-child example of why fixes are not to go to
> -stable first.  It leads to exactly this sort of lossage.

I guess what you are trying to say is

"Thank you for taking the time to track down this performance bug
and having it fixed in -stable so that we can ship 4.5 with the
fix, and now for looking at the same problem in -current even if
you don't really use it"

Please, (re)read the commit log and the discussion on -net, I did
not want to step over the toes of the author of the code in -current,
but he did not have such strong objections for having -stable fixed.

This fix has not been lost _only_ because the code was in stable
and it was documented in the commit logs. If I had not committed
it there (and I could not do it on -current for the reasons above),
I would have just forgotten about it.

> How about fixing it for real as described in the commit message?

The real fix, for me, is the one-line change to M_LEADINGSPACE.
The one described in the commit message was just Bosko's point of
view, with which I and many others disagree, and which requires an
extensive scrutiny of the code and a change of the commonly understood
semantics in M_LEADINGSPACE.

cheers
luigi

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Re: Solved (Re: -current vs. -stable network performance)

2001-12-14 Thread Terry Lambert

Peter Wemm wrote:
> 
> Luigi Rizzo wrote:
> [..]
> > The change below has been committed to STABLE 7 weeks ago, but did
> > not go into CURRENT because there was some disagreement on the
> > semantics of M_LEADINGSPACE. However I would strongly vote for
> > committing this change to CURRENT as well, given the huge performance
> > implications (even if the 21143 were not buggy, not being able to
> > write into clusters hurts a lot of pieces of the networking stack).
> 
> Incidently, this is a poster-child example of why fixes are not to go to
> -stable first.  It leads to exactly this sort of lossage.

If we waited for all disagreement about semantics in -current to be
resolved, we would all be tripping over our beards before some things
would be committed.

Is the semantic complain going to be overridden by the performance
advantages of not caring about the semantics, only the speed?

> rev 1.44.2.11:
> ...
> This does not go in CURRENT as is: as discussed in -net,
> M_LEADINGSPACE  should not check for writability, just report
> available space, leaving the check to some other piece of code.
> Unfortunately, some code in the tree depends on M_LEADINGSPACE
> checking for writability, and so implementing M_LEADINGSPACE
> in the correct way also requires to fix the incorrect usage.
> This is what will be done in CURRENT, but for STABLE, this is
> probably more than we want, and so we are happy (more or less) with
> this simple fix.
> ...
> 
> How about fixing it for real as described in the commit message?

Uh... "patches welcome from the people who complained about the
writability check"?  8^) 8^)...

-- Terry

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Re: Solved (Re: -current vs. -stable network performance)

2001-12-14 Thread Peter Wemm

Luigi Rizzo wrote:
[..]
> The change below has been committed to STABLE 7 weeks ago, but did
> not go into CURRENT because there was some disagreement on the
> semantics of M_LEADINGSPACE. However I would strongly vote for
> committing this change to CURRENT as well, given the huge performance
> implications (even if the 21143 were not buggy, not being able to
> write into clusters hurts a lot of pieces of the networking stack).

Incidently, this is a poster-child example of why fixes are not to go to
-stable first.  It leads to exactly this sort of lossage.

rev 1.44.2.11:
...
This does not go in CURRENT as is: as discussed in -net,
M_LEADINGSPACE  should not check for writability, just report
available space, leaving the check to some other piece of code.
Unfortunately, some code in the tree depends on M_LEADINGSPACE
checking for writability, and so implementing M_LEADINGSPACE
in the correct way also requires to fix the incorrect usage.
This is what will be done in CURRENT, but for STABLE, this is
probably more than we want, and so we are happy (more or less) with
this simple fix.
...

How about fixing it for real as described in the commit message?

Cheers,
-Peter
--
Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]
"All of this is for nothing if we don't go to the stars" - JMS/B5


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