David Brownell <[EMAIL PROTECTED]> writes: > Alexander Hoogerhuis wrote: > > The patch *WITHOUT* debugging enabled fell over real fast. Now *WITH* > > debugging the skyrocketin load symptom is gone, and it's chugging > > along nicely at line speed with FTP and also with CPU maxed out with > > scp about 20% udner line speed (i.e. saturated CPU). SO far I've moved > > 4Gb of data with no ill effect, which is a new record. I'll let it > > Interesting ... it did have an effect. Not entirely unexpected, > though I'm still curious which debug-related delays matter. >
I've gone back and played with it, and the sure way to make it go bonk is to make emacs/gnus look for new mail, at which point I cause massive I/O to my hard drive (and on a laptop thats sloow). > > > play all night with bouncing files around and see if it keels over at > > some point. The interrupt rate is roughly 9k/sec for the USB controller. > > That interrupt rate is absurdly high, considering > > - The controller's irq latency is set at 1 microframe, and > there are are only 8000 microframes per second. Where > would the extra IRQs come from? > > - On 2.5 the scatterlist logic cuts the interrupt rate down > to one per i/o scatterlist, instead of one per entry. > (The scatterlist below is "big", 127 entries.) > > At peak rates, EHCI can do about 25 entries per millisecond, > many controllers do closer to half that. Call the "average" > sglist about 20 entries (close to what I've noticed), and that > suggests a peak IRQ rate closer to 1000/sec. > > Something would seem to be getting measured wrong, or else there's > something else causing a lot of your load problems. > The interrupt rate is higher with debugging enabled, it seems to make a difference of about 3-4.5k int/sec in difference. I had a few mails from a guy that ran on RedHat what had three of these drives on his machine and cooked along nicely, I had a copy of iostat and the likes from a run of copying against his drives and he came in on the same numbers as me wihtout debugging. mvh, A -- Alexander Hoogerhuis | [EMAIL PROTECTED] CCNP - CCDP - MCNE - CCSE | +47 908 21 485 "You have zero privacy anyway. Get over it." --Scott McNealy ------------------------------------------------------- This SF.net email is sponsored by: Etnus, makers of TotalView, The best thread debugger on the planet. Designed with thread debugging features you've never dreamed of, try TotalView 6 free at www.etnus.com. _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
