I can't comment on all of those 'flaws', but I'll just say that there are lots of people (including our customers) that are running DB2 Connect on Linux for S/390 to access VSE and OS/390 databases (and vice-versa) and they are running just fine. They've not had any performance complaints that were related to DB2 Connect or Linux.
On Friday 25 July 2003 09:55 am, you wrote: > Yesterday, one of my colleagues forwarded me the following note (from an > as-of-yet unidentified third party): > > ----------------------- > "I've listed out the main performance problems with 2.5. The point here is > that, > given what you're doing with DB2 Connect, Linux would be a ridiculous > choice prior to a 2.6 kernel." > > "Yes, we benchmarked Oracle on Linux and it was faster than Windows... > But that's not really saying anything, now is it? :)" > ----------------------- > > The alleged performance flaws that he identified were: > > --------------------- > Pre 2.6 Linux Limitations--- > > * High amount of "Big Kernel Locks" still being used (versus small > semaphore locks) for TTY traffic, memory access, etc. (will be reduced in > 2.6) > * Global Locks for (I/O requests, IRQs, etc.) > * No processor affinity (threads are stuck on same CPUs always) > * Kernel is not pre-emptive > * Buffer cache and page cache managed separately (slower) > * I/O Scheduler is inefficient > * Single I/O global request lock for all I/O types (raw vs sync > vs...) * Old Scheduler still being used: > o Global run-queue holds all runnable processes (slow when queue is > long) > o Reschedule scans requires full run-queue scan to find next process > to run (limits SMP scalability) > o Time-slice recalculation after all slices have been consumed (slow > process when queue is long) > o No facility for more efficient wakeup, interrupt, schedule timers > o No load balancing between CPUs > o Unnecessary context switches for procs / threads sleeping > ---------------------- > > Can some of the internals gurus on this list comment on these claims and > whether they are relevant to Linux under VM? I have my own speculations, > but I wanted to see what the facts were. > > > Thanks, > > Julian Gustasson > Lead System SW Support Engineer > Qwest Information Technologies -- Rich Smrcina Sr. Systems Engineer Sytek Services, A Division of DSG Milwaukee, WI rsmrcina at wi.rr.com rsmrcina at dsgroup.com Catch the WAVV! Stay for Requirements and the Free for All! Update your S/390 skills in 4 days for a very reasonable price. WAVV 2004 in Chattanooga, TN April 30-May 4, 2004 For details see http://www.wavv.org
