On Tue, 22 May 2007 20:37:54 +1000 Con Kolivas <[EMAIL PROTECTED]> wrote:
> On Tuesday 22 May 2007 20:25, Ingo Molnar wrote: > > * Con Kolivas <[EMAIL PROTECTED]> wrote: > > > > > there was nothing else running on the system - so i suspect the > > > > > swapin activity flagged 'itself' as some 'other' activity and > > > > > stopped? The swapins happened in 4 bursts, separated by 5 seconds > > > > > total idleness. > > > > > > > > I've noted burst swapins separated by some seconds of pause in my > > > > desktop system too (with sp_tester and an idle gnome). > > > > > > That really is expected, as just about anything, including journal > > > writeout, would be enough to put it back to sleep for 5 more seconds. > > > > note that nothing like that happened on my system - in the > > swap-prefetch-off case there was _zero_ IO activity during the sleep > > period. > > Ok, granted it's _very_ conservative. I really don't want to risk its > presence > being a burden on anything, and the iowait it induces probably makes it turn > itself off for another PREFETCH_DELAY (5s). I really don't want to cross the > line to where it is detrimental in any way. Not dropping out on a > cond_resched and perhaps making the delay tunable should be enough to make it > a little less "sleepy". > > -- > -ck Hi. I just did some video encoding on my desktop and I was noticing (for the first time in a while) that running apps had to hit swap quite a lot when I switched to them (the encoding was going at full blast for most of the day, and most of the time other running apps were idle). Now, a good half of my RAM appeared to be free during all this, so I was thinking at the time that it would be nice if swap prefetch could be tunably more aggressive. I guess it would be ideal in this case if it could kick in during tunably low disk-IO periods, even if the CPU is rather busy. I'm sure you've considered this, so I only butt in here to cast a vote for it. :) Of course, I could be completely wrong about the possibility.. and I seem to remember that the disk cache can take up about half the ram by default without this showing up in 'gnome-system-monitor'... which I guess might happen during heavy encoding.. but even if it did, I could have set the limit lower, and would then have still appreciated prefetching. Ash - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
