Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-28 Thread grundig
El Sat, 28 Jul 2007 02:03:19 +0200 (CEST), "Indan Zupancic" <[EMAIL PROTECTED]> escribió: > Perhaps one of the reasons is that this is core kernel code. And that it > isn't a new > feature, but a performance improvement with doubtful trade-offs. The problem > statement isn't clear either. It

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-28 Thread grundig
El Sat, 28 Jul 2007 02:03:19 +0200 (CEST), Indan Zupancic [EMAIL PROTECTED] escribió: Perhaps one of the reasons is that this is core kernel code. And that it isn't a new feature, but a performance improvement with doubtful trade-offs. The problem statement isn't clear either. It seems like

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Al Boldi
Chris Snook wrote: > Al Boldi wrote: > > IMHO, what everybody agrees on, is that swap-prefetch has a positive > > effect in some cases, and nobody can prove an adverse effect (excluding > > power consumption). The reason for this positive effect is also crystal > > clear: It prefetches from swap

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Chris Snook
Al Boldi wrote: People wrote: I believe the users who say their apps really do get paged back in though, so suspect that's not the case. Stopping the bush-circumference beating, I do not. -ck (and gentoo) have this massive Calimero thing going among their users where people are much less

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Indan Zupancic
On Sat, July 28, 2007 01:34, grundig wrote: > El Fri, 27 Jul 2007 15:06:14 -0700, Arjan van de Ven <[EMAIL PROTECTED]> > escribi�: > >> how do you know there will be other activity? You start the IO and that >> basically blacks out the disk for 5 to 10 ms. If the "real" IO gets >> submitted in

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Arjan van de Ven
On Sat, 2007-07-28 at 01:34 +0200, grundig wrote: > El Fri, 27 Jul 2007 15:06:14 -0700, Arjan van de Ven <[EMAIL PROTECTED]> > escribió: > > > how do you know there will be other activity? You start the IO and that > > basically blacks out the disk for 5 to 10 ms. If the "real" IO gets > >

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread grundig
El Fri, 27 Jul 2007 15:06:14 -0700, Arjan van de Ven <[EMAIL PROTECTED]> escribió: > how do you know there will be other activity? You start the IO and that > basically blacks out the disk for 5 to 10 ms. If the "real" IO gets > submitted in that time you add latency. You cannot predict that IO

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Indan Zupancic
On Sat, July 28, 2007 00:06, Arjan van de Ven wrote: > On Fri, 2007-07-27 at 23:51 +0200, Indan Zupanci >> > also, they take up seek time (5 to 10 msec), so if you were to read >> > something else at the time you get additional latency. >> >> If there's other disk activity swap prefetch shouldn't

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Arjan van de Ven
On Fri, 2007-07-27 at 23:51 +0200, Indan Zupanci > > also, they take up seek time (5 to 10 msec), so if you were to read > > something else at the time you get additional latency. > > If there's other disk activity swap prefetch shouldn't do much, so this isn't > really true. how do you know

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Indan Zupancic
On Fri, July 27, 2007 22:34, Arjan van de Ven wrote: > On Fri, July 27, 2007 21:43, Al Boldi wrote: >> IMHO, what everybody agrees on, is that swap-prefetch has a positive effect >> in some cases, and nobody can prove an adverse effect (excluding power >> consumption). The reason for this

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Arjan van de Ven
> IMHO, what everybody agrees on, is that swap-prefetch has a positive effect > in some cases, and nobody can prove an adverse effect (excluding power > consumption). The reason for this positive effect is also crystal clear: > It prefetches from swap on idle into free memory, ie: it doesn't

swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Al Boldi
People wrote: > >> I believe the users who say their apps really do get paged back in > >> though, so suspect that's not the case. > > > > Stopping the bush-circumference beating, I do not. -ck (and gentoo) have > > this massive Calimero thing going among their users where people are > > much less

swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Al Boldi
People wrote: I believe the users who say their apps really do get paged back in though, so suspect that's not the case. Stopping the bush-circumference beating, I do not. -ck (and gentoo) have this massive Calimero thing going among their users where people are much less interested in

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Arjan van de Ven
IMHO, what everybody agrees on, is that swap-prefetch has a positive effect in some cases, and nobody can prove an adverse effect (excluding power consumption). The reason for this positive effect is also crystal clear: It prefetches from swap on idle into free memory, ie: it doesn't

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Indan Zupancic
On Fri, July 27, 2007 22:34, Arjan van de Ven wrote: On Fri, July 27, 2007 21:43, Al Boldi wrote: IMHO, what everybody agrees on, is that swap-prefetch has a positive effect in some cases, and nobody can prove an adverse effect (excluding power consumption). The reason for this positive

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Arjan van de Ven
On Fri, 2007-07-27 at 23:51 +0200, Indan Zupanci also, they take up seek time (5 to 10 msec), so if you were to read something else at the time you get additional latency. If there's other disk activity swap prefetch shouldn't do much, so this isn't really true. how do you know there will

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Indan Zupancic
On Sat, July 28, 2007 00:06, Arjan van de Ven wrote: On Fri, 2007-07-27 at 23:51 +0200, Indan Zupanci also, they take up seek time (5 to 10 msec), so if you were to read something else at the time you get additional latency. If there's other disk activity swap prefetch shouldn't do much, so

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread grundig
El Fri, 27 Jul 2007 15:06:14 -0700, Arjan van de Ven [EMAIL PROTECTED] escribió: how do you know there will be other activity? You start the IO and that basically blacks out the disk for 5 to 10 ms. If the real IO gets submitted in that time you add latency. You cannot predict that IO

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Arjan van de Ven
On Sat, 2007-07-28 at 01:34 +0200, grundig wrote: El Fri, 27 Jul 2007 15:06:14 -0700, Arjan van de Ven [EMAIL PROTECTED] escribió: how do you know there will be other activity? You start the IO and that basically blacks out the disk for 5 to 10 ms. If the real IO gets submitted in that

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Indan Zupancic
On Sat, July 28, 2007 01:34, grundig wrote: El Fri, 27 Jul 2007 15:06:14 -0700, Arjan van de Ven [EMAIL PROTECTED] escribi�: how do you know there will be other activity? You start the IO and that basically blacks out the disk for 5 to 10 ms. If the real IO gets submitted in that time you

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Chris Snook
Al Boldi wrote: People wrote: I believe the users who say their apps really do get paged back in though, so suspect that's not the case. Stopping the bush-circumference beating, I do not. -ck (and gentoo) have this massive Calimero thing going among their users where people are much less

Re: swap-prefetch: A smart way to make good use of idle resources (was: updatedb)

2007-07-27 Thread Al Boldi
Chris Snook wrote: Al Boldi wrote: IMHO, what everybody agrees on, is that swap-prefetch has a positive effect in some cases, and nobody can prove an adverse effect (excluding power consumption). The reason for this positive effect is also crystal clear: It prefetches from swap on idle