Do the arithmetic, 300 dpi, A4 pages are approx 8*11inches at approx 3 byte colour depth
(300*8)*(300*11)*3 /(180seconds) (3 minutes) approx=132000 which is approx the speed of a printer port isn't it? On Mon, 2003-02-10 at 11:45, Helmut Walle wrote: > Hi all, > > For the first time, I installed a parport scanner under Linux, and it > is incredibly sloooooowww! Now I have read kernel docs and sane docs > for a while, but it seems I am either missing the decisive point, or > scanning with Linux is really that slow... Could anyone here shed some > light on this? I have googled for "linux scanner parallel EPP" and > things like that, but did not find much useful. > > What do we have? > - Pentium 120 MHz, 96 MB RAM, 128 MB swap > - Linux 2.2.19 or 2.4.10 > - Scanner Mustek 600 III EP plus > - sane 1.0.9 with mustek_pp backend > > Now it takes about a minute for a preview, and about three minutes to > scan an A4 page at 300 dpi. This seems pretty slow to me - or am I > expecting too much? > > The BIOS parport setting is EPP (I also tried ECP/EPP), and dmesg > says: > > ... > parport0: PC-style at 0x378 [PCSPP,TRISTATE,EPP] > parport0: cpp_daisy: aa5500ff(38) > parport0: assign_addrs: aa5500ff(38) > parport0: cpp_daisy: aa5500ff(38) > parport0: assign_addrs: aa5500ff(38) > lp0: using parport0 (polling). > ... > > Does this mean EPP is really used? Would be nice... But if not it > would explain that it is slow. Is there a way to explicitly tell the > kernel parport driver to use EPP? I did not find anything in the boot > parameter docs. > > I have switched off the "niceload" option in the sane config. So the > CPU gets nicely loaded, but scanning is still very slow. The CPU load > actually is "full", and BTW so it is for the cat process that runs > when I print. Why does parport stuff load the CPU so heavily? The data > rate is not really high enough to justify this. Or is it the > inefficiency of the polling? I am not (yet) a parport expert... > > Another strange thing is that whenever I start xscanimage, it will > modprobe for usbcore for quite a while, before it finally gives up and > starts. But I have configured the mustek_pp - so it should not worry > about USB at all. > > Scanning does not seem to be one of the strong sides of Linux... > > I would appreciate any comments / experience reports related to this. > > Cheers, > > Helmut. > > +----------------+ > | Helmut Walle | > | [EMAIL PROTECTED] | > +----------------+ -- Zane Gilmore, Analyst / Programmer Information Services Section, Information Technology Dept, University of Canterbury - Te Whare Waananga o Waitaha Private Bag 4800, Christchurch New Zealand Phone +64-3-364 2987 extn 7895
