Re: [9fans] πp

[David Leimbach <leimy2k@gmail.com>]

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2010/10/15 Sape Mullender <sape@plan9.bell-labs.com>

> Are we talking about πP or 9P?
>

It's about both.  I was just curious about how 9P was deficient in terms of
pipelining.  It might not be optimal for all cases of pipelining, but the
protocol seems to support it in certain cases just fine.

ΠP deals with it in a superior way, and I need to finish reading the paper
on it.


>
> ΠP doesn't have Twalk.  It has open, which combines clone, walk, and open
> from
> 9P.  Before you start jumping up and down and telling me that you can't
> open
> without revieing the qids from the walk (to check them for mount points),
> let
> me tell you that we are also tackling mount tables.  Mount tables will no
> longer
> match qids but longest prefix path names.
> We know the semantics are different.  But you have to look hard to find
> realistic situations where the difference matters.
>
> I intend to write a πP design document that explains the whole concept in
> excruciating detail.  There's a lot more to it than just changing walk and
> open.
>

I'm looking forward to it!


>
>        Sape
>
>
> > From: lucho@ionkov.net
> > To: 9fans@9fans.net
> > Reply-To: 9fans@9fans.net
> > Date: Thu Oct 14 23:13:59 CES 2010
> > Subject: Re: [9fans] πp
> >
> > It can't be dealt with the current protocol. It doesn't guarantee that
> > Topen will be executed once Twalk is done. So can get Rerrors even if
> > Twalk succeeds.
> >
> > 2010/10/13 Venkatesh Srinivas <me@acm.jhu.edu>:
> > >> 2) you can't pipeline requests if the result of one request depends on
> the
> > >> result of a previous. for instance: walk to file, open it, read it,
> close
> > >> it.
> > >> if the first operation fails, then subsequent operations will be
> invalid.
> > >
> > > Given careful allocation of FIDs by a client, that can be dealt with -
> > > operations on an invalid FID just get RErrors.
> > >
> > > -- vs
> > >
>
>

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