Re: Weird one

Read the Solaris Internals book by Jack Mauro ??? Ian Michael Gumby wrote: > Just out of curiosity, and this may not be at issue... > > On a multi-core /smp Linux box, does each CPU have its own stack or does > it share the same stack? > > If they share the same stack, how does one track to see if their are > thread contention issues. > Meaning if Thread A from the same process is on core 1, and Thread B > from the same process is on core 2, what sort of contention occurs? > > If each CPU core has its own stack, is there load balancing among the > stacks and would there be process migration between stacks? > > Ok, this is an OS question and not an Informix question per se. > > It would be interesting to see how solaris would handle this too. > > > > From: mpruet1@verizon.net > > Subject: Re: Weird one > > Date: Thu, 25 Sep 2008 05:07:28 +0000 > > To: informix-list@iiug.org > > > > Art Kagel wrote: > > > <Cross posted to CDI & IDS Forum> > > > > > > OK, an oddity for you. I'm doing some performance and tuning testing > > > using multiple copies of dbload. > > > > > > I'll tell you what I'm dealing with. Anyone with any idea as to why > the > > > engine is behaving as it is please pipe in. > > > > > > Platform: Linux 2.6.9-67.ELsmp, x86-32 with 2 single core 3.4GHZ > > > processors, single disk spindle for IDS another for the OS > > > IDS Vers: 10.00.UC8 > > > > > > OK, so I'm getting reasonable timings running various numbers of load > > > clients against the engine with 1, 2, 4, 6, & 8 CPU VPs truncating the > > > table between runs. > > > > > > I notice in TOP that at some point in the run IO Wait goes way up and > > > CPU consumption way down for 10-30 seconds then back to 'normal'. I > > > figure, "Oh! Extends are being added." So after completing the set of > > > timing runs I change the script to drop and recreate the table with an > > > extent size sufficient for the loaded data in the initial load instead > > > of the truncate and run the tests again expecting to see that the > > > runtimes have decrease by 10-20 seconds per run. NO! the runtimes > > > INCREASED by 16 to 64 seconds! > > > > Also sounds to me like you might need additional page cleaners and maybe > > adjust the triggers for firing them. IDS 11 might have non-blocking > > checkpoint so LRU MIN/MAX can be pretty high. But that's not the case > > with IDS10. > > > > > > > > Yes, I checked that there was indeed still a single extent the size of > > > the initial extent size allocation after each load. > > > > > > Any ideas as to why this should be? > > > > > > -- > > > Art S. Kagel > > > Oninit (www.oninit.com <http://www.oninit.com>) > > > IIUG Board of Directors (art@iiug.org <mailto:art@iiug.org>) > > > > > > Disclaimer: Please keep in mind that my own opinions are my own > opinions > > > and do not reflect on my employer, Oninit, the IIUG, nor any other > > > organization with which I am associated either explicitly or > implicitly. > > > Neither do those opinions reflect those of other individuals > affiliated > > > with any entity with which I am affiliated nor those of the entities > > > themselves. > > > > > _______________________________________________ > > Informix-list mailing list > > Informix-list@iiug.org > > http://www.iiug.org/mailman/listinfo/informix-list > > ------------------------------------------------------------------------ > Get more out of the Web. Learn 10 hidden secrets of Windows Live. Learn > Now > <http://windowslive.com/connect/post/jamiethomson.spaces.live.com-Blog-cns!550F681DAD532637!5295.entry?ocid=TXT_TAGLM_WL_getmore_092008>;