Re: End-of-line or just carriage-return
matteverywhere <matteverywhere-gM/[email protected]> Thu, 19 Jul 2007 17:22:41 +0200
| Newsgroups | gmane.linux.cluster.openmosix.devel |
|---|---|
| Message-ID | <[email protected]> |
Hey Wes, Wes Wagner wrote: > Any objections to a Tuesday 5:30pm meeting? We can call ourselves a > Birds of a Feather group and hash out some of these details about > openmosix. would be cool but i think i cannot make it at 5:30 your time since i am living in a complete different time-zone (Germany). How do you plan the meeting ? e.g. skype-conference call ? > > -Wes thanks + best, Matt > > > On 7/19/07, * Matt Rechenburg* <[email protected] > <mailto:[email protected]>> wrote: > > Hi Wes, > > Wes Wagner wrote: > > I live in Portland, Oregon and if you are willing to discuss a > > continuation of the open mosix project in another form I would > be very > > happy to meet with you and anyone else here who is interested. > > :) good, i am interested. > > > many thanks + all the best, > > Matt > > > > > -Wes Wagner > > > > > > On 7/18/07, *Jonathan Day* <imipak-/[email protected] > <mailto:imipak-/[email protected]> > > <mailto:imipak-/[email protected] <mailto:imipak-/[email protected]>>> wrote: > > > > First off, I'd like to thank Moshe Bar and all the > > other programmers involved in openMosix - I firmly > > believe that it is the best of the SSI solutions out > > there at present. > > > > I also believe that SSI is going to be more important, > > not less, on the next generation of machines. The next > > version of PCI Express supports multiple masters on a > > single network of PCI switches. However, QoS seems to > > be limited to bandwidth reservation for a master to be > > established at setup. There is no way of dynamically > > configuring the next generation PCI-e switches > > according to varying demands. > > > > How does this impact SSI? Well, if you can't move the > > allocation, move the process. If you can migrate > > between masters, you can load-balance a PCI-e system > > in a way that the hardware does not support (by > > design). > > > > There is also the case that programs are usually > > smaller than the data sets being manipulated. In a > > general-purpose cluster, it is sometimes the case that > > shifting the program image is vastly less expensive > > than shifting the data. SIMD would seem to be the > > perfect market for this, because you're guaranteed to > > be running the same code on all nodes, but each node > > will have its own data - which it would therefore need > > to collect, rather than having a central collection > > point. > > > > DSM is a problem - and a problem I have worked hard on > > for the last few years. Part of the problem is that > > when you copy to N nodes using a unicast delivery > > system, you must transmit the data N times. That is > > slow. NACK-Oriented Reliable Multicast would reduce > > the copies needed, cutting bandwidth requirements and > > the total elapsed time between start of first packet > > to end of last packet. > > > > RDMA (Remote Direct Memory Access) is also an > > interesting technology, allowing one node to copy from > > local memory to remote memory, or remote memory to > > local memory, in a single operation without > > intervention by the kernel on either side. However, > > most machines are not provided with RNICs or > > Infiniband cards. Pity. > > > > A project of mine has been to extend RDMA to support > > multicasting - something the specs don't currently > > allow for - so that you can transfer to multiple > > memories in one go. Devising a protocol that the RDMA > > groups can sign on to is proving difficult. There are > > a large number of corner cases and the more I fix, the > > more I find. If RDMA proves impossible, then any > > zero-copy kernel-bypass protocol would work in > > principle. This would avoid having specialized > > hardware but you'd need an emulation layer to provide > > compatibility to the bulk of interesting software. > > > > Multicast with zero-copy does not totally solve the > > problem of DSM, but it reduces some of the issues. You > > shed a whole bunch of context switches, stack > > latencies, buffer copies, backoffs caused by switch > > flooding, etc. It's hard to quantify, but my > > calculations repeatedly show that the latency is > > roughly 5.6 microseconds plus the per hop latency on > > the longest path for every 4K, regardless of the > > number of nodes actually delivered to. > > > > Another networking technology I have been taking a > > close look at is Active Messaging. There's a project - > > GAMMA - that implements AM on Linux. Again, the idea > > is to reduce the wasted cycles involved. AM looks very > > interesting, but the implementation seems to be very > > card-specific and doesn't play nice with other > > protocols. To use AM in a general-purpose cluster > > would need a fair amount of work put into it. > > > > TIPC is also worthy of examination, as anything that > > reduces what a clustering solution needs to do to > > cluster transparently is a Good Thing. > > > > Ok, I've now completely flogged, beaten and trampled > > this poor dead horse into the ground, I'll mutilate a > > few other things, the first of which is the SSI > > concept. > > > > Strictly speaking, openMosix does not need to be SSI. > > Indeed, it would make some sense to use the IBCS > > patches to load and start applications for a range of > > Intel-based *nixes and then migrate the process space > > to an instance of the actual OS it is intended for. We > > now have a multi system image clustering technology. > > > > The second issue is with real-time support. Real-time, > > in this context, means that if process X is guaranteed > > a timeslice of Y out of a total timeslice of Z, with a > > margin of error M, then no matter how time is divided > > up, how busy/free the system is, whether the system > > voluntarily hands back control, etc, it WILL occupy > > that amount of the available time, give or take only > > the margin of error, nothing more. > > > > This can be fun when clustering. You don't hear of > > hard real-time clusters for a reason, and the reason > > has nothing to do with a lack of need. What does > > real-time mean for openMosix? It means that where such > > state information exists, openMosix needs to copy it. > > It means that processes need to migrate according to a > > packing algorithm that maximizes the chances of always > > meeting the timeslice goals. If real-time networking > > is also being used, then you also need the packing > > algorithm to consider network latencies. > > > > Real-time does not mean the fastest solution, which is > > what most SSI strategies look for. Nearest neighbors > > and all that. You will occupy a certain length of time > > even if the transfer takes less, so you must place at > > the greatest distance that the transfers will still > > meet deadlines even under the greatest-expected > > network loads. > > > > Last, but by no means least, if the project is to go > > unmaintained, does anyone object to it being listed on > > the Unmaintained Free Projects pages? > > > > Jonathan > > > > P.S. Ok, I lied, that wasn't last, this is. If there > > are people from this list going to the Open Source > > conference in Portland, Oregon, next week, I suggest > > we arrange some sort of mini meetup. Accepting that > > Moshe has found nobody with the time and ability to > > run the project at this time, I propose that those of > > us who know gifted coders work on finding some, and > > that those who have contacts in the moneyed world see > > if the project can be sponsored somehow to the point > > where a team of developers can hack it to perfection > > on a viable salaried basis. > > > > > > > > > > > ____________________________________________________________________________________ > > > Need a vacation? Get great deals > > to amazing places on Yahoo! Travel. > > http://travel.yahoo.com/ > > > > > ------------------------------------------------------------------------- > > > This SF.net email is sponsored by DB2 Express > > Download DB2 Express C - the FREE version of DB2 express and > take > > control of your XML. No limits. Just data. Click to get it now. > > http://sourceforge.net/powerbar/db2/ > > _______________________________________________ > > openMosix-devel mailing list > > openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > <mailto:openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org> > > <mailto:openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > <mailto:openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>> > > https://lists.sourceforge.net/lists/listinfo/openmosix-devel > > <https://lists.sourceforge.net/lists/listinfo/openmosix-devel> > > > > > > > > > > -- > > Wes Wagner > > > > Join a libertarian network of person-to-person lending on Prosper: > > > > > http://www.prosper.com/groups/group_home.aspx?group_short_name=freelibertarians&referrer=AiriusTorpora&utm_source=referrer-AiriusTorpora&utm_medium=referral-link&utm_content=join_my_group-160x33&utm_campaign=referrals-group > <http://www.prosper.com/groups/group_home.aspx?group_short_name=freelibertarians&referrer=AiriusTorpora&utm_source=referrer-AiriusTorpora&utm_medium=referral-link&utm_content=join_my_group-160x33&utm_campaign=referrals-group> > > < > http://www.prosper.com/groups/group_home.aspx?group_short_name=freelibertarians&referrer=AiriusTorpora&utm_source=referrer-AiriusTorpora&utm_medium=referral-link&utm_content=join_my_group-160x33&utm_campaign=referrals-group > <http://www.prosper.com/groups/group_home.aspx?group_short_name=freelibertarians&referrer=AiriusTorpora&utm_source=referrer-AiriusTorpora&utm_medium=referral-link&utm_content=join_my_group-160x33&utm_campaign=referrals-group>> > > > > > ------------------------------------------------------------------------ > > > > > ------------------------------------------------------------------------- > > This SF.net email is sponsored by DB2 Express > > Download DB2 Express C - the FREE version of DB2 express and take > > control of your XML. No limits. Just data. Click to get it now. > > http://sourceforge.net/powerbar/db2/ > <http://sourceforge.net/powerbar/db2/> > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > openMosix-devel mailing list > > openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > <mailto:openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org> > > https://lists.sourceforge.net/lists/listinfo/openmosix-devel > > > > > -- > www.openQRM.org <http://www.openQRM.org> > - Keeps your Data-Center Up and Running > > Matt's blog - http://mattinaction.blogspot.com/ > > > > > > > -- > Wes Wagner > > Join a libertarian network of person-to-person lending on Prosper: > > http://www.prosper.com/groups/group_home.aspx?group_short_name=freelibertarians&referrer=AiriusTorpora&utm_source=referrer-AiriusTorpora&utm_medium=referral-link&utm_content=join_my_group-160x33&utm_campaign=referrals-group > <http://www.prosper.com/groups/group_home.aspx?group_short_name=freelibertarians&referrer=AiriusTorpora&utm_source=referrer-AiriusTorpora&utm_medium=referral-link&utm_content=join_my_group-160x33&utm_campaign=referrals-group> > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > ------------------------------------------------------------------------ > > _______________________________________________ > openMosix-devel mailing list > openMosix-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > https://lists.sourceforge.net/lists/listinfo/openmosix-devel > -- www.openQRM.org - Keeps your Data-Center Up and Running Matt's blog - http://mattinaction.blogspot.com/ ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/