On Thu, Sep 29, 2011 at 2:42 PM, Arnaud Patard <[email protected]> wrote: > Jari Kirma <[email protected]> writes: > > Hi, > >> I recently installed Debian Squeeze on a new TS-419P+, and it ran >> nicely. So, to make it more interesting, I upgraded to Wheeze, and now >> I'm seeing a performance/responsiveness regression whose cause I can't >> quite figure out. >> >> This has following symptoms: >> >> - Big-file dd with large block size (over 16 kiB or so, but especially >> like 1 MiB), from both RAID-5 backed files and bare disks performs >> much slower (30-60%!) than before. >> - dd with small blocks (4 kiB would seem to be close to sweet spot) >> performs roughly as expected, but slightly slower when served from >> RAID-5 (maybe 25% difference at most). >> - SSH and even serial console interaction on other shells feels much >> choppier than it used to be according to my memory with Squeeze while >> I was doing these benchmarks. >> - System is fine without this disk activity (I didn't try if network >> activity would have a similar effect, but just busylooping processes >> cause no trouble). >> >> Do you have a chance to try this on Kirkwood system, preferably with >> Marvell 6282, not 6281? Somehow I'm feeling that > > iirc, 6282 and 6281 are very similar beasts so it should not matter a > lot if one is using 6281 or 6282 > >> linux-image-3.0.0-1-kirkwood kernel is missing interrupts, or >> something. There is no indication of this on dmesg, though. > > There has not been a lot of changes on kirkwood specific parts so your > issue may not be kirkwood specific. If it's possible, would be > interesting to test 3.1-rc7 from experimental on your ts419p+. It's just > finished to build so it should be available soon.
3.1-rc7 indeed helped! I wonder what was the cause of this (most likely non-arm-related) regression, but on 3.0, performance of block reads was reasonable for block sizes of 1-96 kiB, started to noticeably drop at 128 kiB and became downright abysmal (less than 40% of the peak performance) around 256 kiB. With 3.1-rc7, slight degradation (as earlier with squeeze) can be noticed past 128 kiB, but transfer rates still stay around 85-95% bracket. Everything seems back to normal now. :) -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/cacjdtkjx-kvefj64n970rnuusfbyavd9uux7a1nkkhopfdh...@mail.gmail.com
