Michal, has been any one working on the Linux kernel fifo/pipe implementation to implement I_PEEK? Is there a Bugzilla entry for this?
Olga On Wed, Jun 13, 2012 at 5:54 PM, Michal Hlavinka <[email protected]> wrote: > On 06/05/2012 03:03 PM, Cedric Blancher wrote: >> >> On 5 June 2012 09:11, Michal Hlavinka<[email protected]> wrote: >>> >>> On 06/01/2012 02:32 PM, Irek Szczesniak wrote: >>>> >>>> >>>> Michal, did anyone ever filed a bug against Linux's FIFO/PIPE >>>> implementations to support I_PEEK? As far as I can check all SystemV >>>> derivatives (including Solaris), AIX and HP/UX support I_PEEK on pipes >>>> and fifos. >>> >>> >>> >>> I don't know if there was any official attempt. I asked a few kernel >>> developers in person and they told me that no one will bother with this. >> >> >> <rant> >> Michal, I recall that Redhat staff once ridiculed and mocked a patch >> (...why add extra performance support for a dead OS [Solaris] ...) >> which added support for I_PEEK to bash2 and finally convinced the >> maintainers NOT to take it. So basically this issue is blocked from >> both sides, kernel and bash, by Redhat. >> Why? >> </rant> > > > I'm not aware about anything related, so I can't answer your > ran^W^W^Wquestion. > > >> As for an implementation in the Linux fifo kernel module, the I_PEEK >> ioctl() can be implemented along the lines of a read() syscall but >> without disposing the data which have been read. An implementation >> should therefore be very easy and should give the shells in Linux a >> SERIOUS performance advantage. I'm wondering why Redhat isn't >> interested in performance. Oh yes, see<rant /> > > > Cedric was somewhat right in his reply. There are a lot of processes which > are quite resource demanding even for one line change. Also, there is always > more work than what can be done (especially on kernel side. afaik, we're > still hiring ;-) ). If someone does X, it means he won't be able to do Y. > So, we do what product management tell us to do. > > Also, please don't forget that Red Hat is only Linux, but Linux is not only > Red Hat. (Well, nowadays even the first part is no longer completely true.) > I wanted to add I_PEEK feature request to upstream bugzilla, but I've been > told that it does not work that way. It'd rot there for ages until someone > would close that a few years later during some bugzilla clean up. > > Anyway, I found up a few colleagues willing to code it. I need a feature > request to be filed now. I'm going to ask a few customers who complained > about 'connection reset by peer' messages if they are willing to do it. If I > fail, I'll try to convince them to code it in their spare time. > > > > > > _______________________________________________ > ast-developers mailing list > [email protected] > https://mailman.research.att.com/mailman/listinfo/ast-developers -- , _ _ , { \/`o;====- Olga Kryzhanovska -====;o`\/ } .----'-/`-/ [email protected] \-`\-'----. `'-..-| / http://twitter.com/fleyta \ |-..-'` /\/\ Solaris/BSD//C/C++ programmer /\/\ `--` `--` _______________________________________________ ast-developers mailing list [email protected] http://lists.research.att.com/mailman/listinfo/ast-developers
