On Fri, Mar 30, 2012 at 11:40 AM, avadh patel <[email protected]> wrote:
> > On Fri, Mar 30, 2012 at 8:24 AM, Paul Rosenfeld <[email protected]>wrote: > >> Do you think it is very important to have a stripped down kernel? Do you >> think having a kernel with more stuff compiled in causes more noise/longer >> runtime? >> >> With default kernel I haven't seen much noise with most of parsec > benchmarks. But the fact that half of parsec benchmark has its own issues > with thread-affinity and other things, running parsec with default kernel > should be ok. > > I would think that with the Ubuntu kernels having most of their options as >> modules, it shouldn't really be that much of an issue, right? >> >> For most of us who run CPU intensive workloads it shouldn't be a big > issue. For IO intensive or disk intensive workloads, tweaking file system > parameters will be help to reduce non-determinism, so it won't randomly > perform disk write to flush file-system caches. But if you'r doing heavy > IO benchmark, its always good to tweak such kernel parameters. > And if you're doing I/O heavy benchmarks then you're probably not seeing very accurate results since there's no disk models :) > > - Avadh > > >> On Fri, Mar 30, 2012 at 10:55 AM, avadh patel <[email protected]>wrote: >> >>> Does anyone thinks that it will be useful to have a latest Ubuntu disk >>> images? >>> I have a local 11.10 (natty) disk image that i built recently but it >>> doesn't have stripped down kernel image. >>> >>> Let me know if people are interested in it or not. >>> >>> - Avadh >>> >>> On Wed, Mar 28, 2012 at 11:22 AM, Paul Rosenfeld >>> <[email protected]>wrote: >>> >>>> Ah, good to know, Thanks. >>>> >>>> On Wed, Mar 28, 2012 at 1:08 PM, Tae Jun Ham <[email protected]> wrote: >>>> >>>>> Hello, >>>>> >>>>> >>>>> For your information, I tried dist-upgrade, too; however, it also >>>>> broke my image (booting part). >>>>> >>>>> >>>>> Thanks >>>>> >>>>> >>>>> -Tae Jun Ham >>>>> >>>>> >>>>> -----Original Message----- >>>>> *From:* "Paul Rosenfeld"<[email protected]> >>>>> *To:* "marss86-devel"<[email protected]>; >>>>> *Cc:* >>>>> *Sent:* 2012-03-29 (목) 01:54:48 >>>>> *Subject:* [marss86-devel] SSH/RSH/OpenMPI: cautions and suggestions >>>>> >>>>> Greetings all, >>>>> >>>>> I have been doing some experimenting and I wanted to share what I've >>>>> learned so that in case anyone else finds this thread maybe I can save >>>>> them >>>>> some time. Though it probably won't be that useful to that many people. >>>>> >>>>> What I've been doing is trying to get some MPI workloads running in >>>>> marss using the OpenMPI shared memory interfaces. Now, I know this sort of >>>>> defeats the spirit of MPI, but we have an interest in such workloads and >>>>> since I can't imagine setting up multiple marss instances with a network >>>>> between them to do *actual* message passing is very easy this is one >>>>> avenue >>>>> to run multiple MPI ranks without multiple marss instances. >>>>> >>>>> I started with the parsec ROI image, converted it to a raw image and >>>>> chrooted the image so I could use apt-get and build stuff without the >>>>> slowdown of using qemu. >>>>> >>>>> 0. My initial attempt at simply apt-getting libopenmpi failed and I >>>>> thought it was due to an old binary so I built 1.4.5 from source. Though >>>>> it >>>>> turns out the orte_init() error was because of missing ssh/rsh [see #3 >>>>> below], so it could be that you can simply apt-get install libopenmpi -- >>>>> though I did find some bug reports that the shared memory mode is broken >>>>> in >>>>> 1.3.x, so use at your own peril. >>>>> 1. Due to the age of the ubuntu distro, you have to change the entries >>>>> in /etc/apt/sources.list to point to old-releases.ubuntu.com and then >>>>> run an apt-get update. >>>>> 2. Do not try to apt-get openssh-client, this will break your image. >>>>> It turns out openssh-client pulls in a few things like mountall and >>>>> upstart which confuse the boot process and your root partition won't >>>>> mount. >>>>> I didn't investigate further about why this fails. Perhaps doing a full on >>>>> dist-upgrade to pull in new kernels and new libc would have fixed this, >>>>> but >>>>> I didn't try it. >>>>> 3. OpenMPI requires either ssh or rsh for some reason even if you're >>>>> using the shared memory system and have no networked nodes. Since >>>>> installing ssh from apt-get breaks the boot process, you should install >>>>> rsh-client -- it pulls in no dependencies and it gets rid of the errors in >>>>> orte_init() when trying to run mpirun >>>>> 4. To enable the sm mode in MPI, issue the following command: mpirun >>>>> -mca btl self,sm -np 4 ./your_mpi_binary >>>>> >>>>> That's about it. >>>>> Happy simulating. >>>>> _______________________________________________ >>>>> http://www.marss86.org >>>>> Marss86-Devel mailing list >>>>> [email protected] >>>>> https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel >>>>> >>>> >>>> >>>> _______________________________________________ >>>> http://www.marss86.org >>>> Marss86-Devel mailing list >>>> [email protected] >>>> https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel >>>> >>>> >>> >> >
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