On 25 February 2010 18:37, Jonathan S. Shapiro <[email protected]> wrote: > On Thu, Feb 25, 2010 at 4:56 AM, Michal Suchanek <[email protected]> > wrote: >> >> Note also that the hibernation feature is as fast as it is only thanks >> to paging which allows shrinking the amount of data which is going to >> be saved. It does not save the whole memory and certainly does not >> load the whole disk. > > Actually, current hibernation mechanisms simply copy the entire memory to
That's not entirely true. The various suspend frameworks for Linux do various pre-suspend memory flush dances. It is however true that they gave up on swapping up stuff aggressively as the restore is then faster but the applications spend a lot of time swapping in pages after restore. Also the the suspend mechanism is just bolted on a kernel which was never intended for this purpose so it is necessarily inefficient. > disk without regard to dirty bits. Reloading this dump is generally slower > than EROS/CapROS/Coyotos restart from checkpoint. No need to repeat what you snipped from the previous mail. > >> >> I don't see how you implement persistence without a persistent store. >> Paging is state of the art way of accessing these stores. > > > Persistence clearly requires a persistent store, but paging is largely > irrelevant. In the world today, the overwhelming majority of persistence is > handled through databases or files. And while databases tend to manage their memory and IO by themselves files tend to be paged into the file cache by the system using the very same pager as is used for accessing the page file. In CapROS there is no page file, the system runs off a general purpose store that encompasses all objects including ones that can look like "files" and ones that are internal to an application yet it pages these objects in and out. I don't see how you get rid of paging unless you get rid of any kind of secondary storage whatsoever. Thanks Michal ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ CapROS-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/capros-devel
