[Cbe-oss-dev] cbe-oss-dev Digest, Vol 22, Issue 9

Mon Nov 5 04:08:46 EST 2007

Sorry to hear about your motorcycle accident, I wish you an as quick
and painless recovery as possible.
On Nov 4, 2007 2:00 AM,  <cbe-oss-dev-request at ozlabs.org> wrote:
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> Today's Topics:
>
>    1. Re: kernel 2.6.23/24 (Laurent Desnogues)
>    2. spufs syscalls (Julio M. Merino Vidal)
>    3. Re: spufs syscalls (Arnd Bergmann)
>    4. Re: kernel 2.6.23/24 (Geoff Levand)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 3 Nov 2007 10:15:47 +0100
> From: "Laurent Desnogues" <laurent.desnogues at gmail.com>
> Subject: Re: [Cbe-oss-dev] kernel 2.6.23/24
> To: cbe-oss-dev at ozlabs.org
> Message-ID:
>         <761ea48b0711030215o188eec51ye3bc6c379218779b at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On 11/2/07, holli at holli.at <holli at holli.at> wrote:
> > i was wondering why the git tree .../geoff/ is not maintained anymore?
> >
> > if i do git pull for this tree - i get since almost 2 weeks no updates
> > available...
>
> IIRC Geert mentionned Geoff is on vacation.
>
>
> Laurent
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 3 Nov 2007 10:50:25 +0100
> From: "Julio M. Merino Vidal" <jmerino at ac.upc.edu>
> Subject: [Cbe-oss-dev] spufs syscalls
> To: Cell Broadband Engine OSS Development <cbe-oss-dev at ozlabs.org>
> Message-ID: <5D8FB1D0-2257-4E67-90A9-1D9024F4DC31 at ac.upc.edu>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> Hello,
>
> This is something I've been wondering for a while and I thought I
> could ask here.
>
> According to an introductory article [1] to spufs, the first version
> of it used a completely filesystem-based interface to manage the
> SPUs: there were no syscalls.  However, some months later, this
> change [2] was done:
>
> ----
> We are moving to a system call based approach for some
> low-level operations now. Two system calls are introduced,
> spu_run and spu_create. The spu_create call can be
> used in place of the mkdir syscall to create an spu
> context. It returns an open file descriptor to the
> new directory. When the fd is closed (e.g. on process
> exit), the context is automatically destroyed.
>
> The spu_run call takes over the role of the ioctl
> with the same name. It operates on the file descriptor
> returned from spu_create, so we don't need the "run"
> file any more.
> ----
>
> Having everything in the file system seemed like a good idea,
> specially to keep user-level compatibility across different systems
> with Cell support.  I also read in [3] that some syscall-based
> interfaces were tried first.
>
> So, why are these two syscalls an exception?  Did the design that
> contained them as part of the file system turn out to be problematic?
>
> Thanks,
>
> 1: http://www.ibm.com/developerworks/power/library/pa-cell/
> 2: http://lkml.org/lkml/2005/9/16/20
> 3: http://www.ibm.com/developerworks/power/library/pa-expert4/
>
> --
> Julio M. Merino Vidal <jmerino at ac.upc.edu>
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 3 Nov 2007 11:56:05 +0100
> From: Arnd Bergmann <arnd at arndb.de>
> Subject: Re: [Cbe-oss-dev] spufs syscalls
> To: cbe-oss-dev at ozlabs.org
> Message-ID: <200711031156.06865.arnd at arndb.de>
> Content-Type: text/plain;  charset="iso-8859-1"
>
> On Saturday 03 November 2007, Julio M. Merino Vidal wrote:
> > So, why are these two syscalls an exception? ?Did the design that ?
> > contained them as part of the file system turn out to be problematic?
>
> Yes, though for the two calls we had slightly different reasons.
> For spu_create, it solves the problem of lifetime management for
> the spu context. We have a 'creat' system call for files that creates
> a new instance of a file and returns a handle for the open file in
> one atomic operation, but this does not exist for directories.
> Only when you have the atomicity, you can have delete-on-close
> semantics, which helps avoid leaving spu context behind after a program
> crashes before removing the contexts.
>
> For spu_run, there are both performance and style reasons to use
> a separate system call. The previous implementation had a file
> called 'run' that you did a read() operation on to start the spu.
> Unless you are a plan9 person, this is completely counterintuitive,
> and it means that you can't really pass parameters into the run
> operation, forcing you to do additional system calls in the fast
> path.
>
> At one point, the idea for the two system calls was to have them
> generic enough so they can be used by other subsystems apart from
> spufs for similar purposes, but they evolved away from that.
> If we should actually get some similar file systems in the future,
> I'd guess we have to create new syscalls that are generic enough
> to cover them all.
>
>         Arnd <><
>
>
> ------------------------------
>
> Message: 4
> Date: Sat, 03 Nov 2007 11:07:36 -0700
> From: Geoff Levand <geoffrey.levand at am.sony.com>
> Subject: Re: [Cbe-oss-dev] kernel 2.6.23/24
> To: holli at holli.at
> Cc: cbe-oss-dev at ozlabs.org
> Message-ID: <472CB8E8.9050304 at am.sony.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi.
>
> holli at holli.at wrote:
> > i was wondering why the git tree .../geoff/ is not maintained anymore?til the
> > if i do git pull for this tree - i get since almost 2 weeks no updates
> > available...
>
> I had a motorcycle accident in Mexico, and am now recovering at home.  I
> have not been able to do any public releases since.
>
> > is there a new tree i should use?
>
> No.  The kernel.org git trees still have the latest publicly released
> PS3 support.
>
> > i saw the email for the new 1.5 addon cd/kernel - but using this kernel my PS3
> > wil crash after few minutes...
> >
> > any help would be great - i got the kernel compiled from geoff's tree and this
> > one is not aborting - but i believe it is not the latest version.
>
> I will try to get the public git trees up to date as soon as possible, I
> hope sometime this week.
>
> I'll make an announcement on this mail list, or you can use these RSS
> feed to monitor the status of the public git trees:
>
>   http://git.kernel.org/?p=linux/kernel/git/geoff/ps3-linux.git;a=rss
>   http://git.kernel.org/?p=linux/kernel/git/geoff/ps3-linux-patches.git;a=rss
>
>
> Sorry for any inconvenience.
>
> -Geoff
>
>
>
>
>
>
> ------------------------------
>
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> End of cbe-oss-dev Digest, Vol 22, Issue 9
> ******************************************
>