Re: [PATCH][RFC] vm: swap prefetch
On Thu, 2005-09-01 at 23:46 +1000, Con Kolivas wrote: > Here is a working swap prefetching patch for 2.6.13. I have resuscitated and > rewritten some early prefetch code Thomas Schlichter did in late 2.5 to > create a configurable kernel thread that reads in swap from ram in reverse > order it was written out. It does this once kswapd has been idle for a minute > (implying no current vm stress). This patch attached below is a rollup of two > patches the current versions of which are here: > > http://ck.kolivas.org/patches/swap-prefetch/ > > These add an exclusive_timer function, and the patch that does the swap > prefetching. I'm posting this rollup to lkml to see what the interest is in > this feature, and for people to test it if they desire. I'm planning on > including it in the next -ck but wanted to gauge general user opinion for > mainline. Note that swapped in pages are kept on backing store (swap), > meaning no further I/O is required if the page needs to swap back out. I would definitely use this if available. That said, I have often thought it might be good to have something like pre-writing swap, ie reverse what your patch does. In other words it'd keep as much of swappable data on disk as possible, but without removing it from memory. So when it comes time to free up some memory, the data is already on disk so no performance penalty from writing it out. Hopefully something worth thinking about. -HK - 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/
Re: [PATCH][RFC] vm: swap prefetch
On Thu, 2005-09-01 at 23:46 +1000, Con Kolivas wrote: Here is a working swap prefetching patch for 2.6.13. I have resuscitated and rewritten some early prefetch code Thomas Schlichter did in late 2.5 to create a configurable kernel thread that reads in swap from ram in reverse order it was written out. It does this once kswapd has been idle for a minute (implying no current vm stress). This patch attached below is a rollup of two patches the current versions of which are here: http://ck.kolivas.org/patches/swap-prefetch/ These add an exclusive_timer function, and the patch that does the swap prefetching. I'm posting this rollup to lkml to see what the interest is in this feature, and for people to test it if they desire. I'm planning on including it in the next -ck but wanted to gauge general user opinion for mainline. Note that swapped in pages are kept on backing store (swap), meaning no further I/O is required if the page needs to swap back out. I would definitely use this if available. That said, I have often thought it might be good to have something like pre-writing swap, ie reverse what your patch does. In other words it'd keep as much of swappable data on disk as possible, but without removing it from memory. So when it comes time to free up some memory, the data is already on disk so no performance penalty from writing it out. Hopefully something worth thinking about. -HK - 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/
Re: Power consumption HZ100, HZ250, HZ1000: new numbers
On Wed, 2005-08-03 at 08:57 -0500, Dmitry Torokhov wrote: > On 8/3/05, Hans Kristian Rosbach <[EMAIL PROTECTED]> wrote: > > On Tue, 2005-08-02 at 00:50 -0400, James Bruce wrote: > > > Theodore Ts'o wrote: > > > > On Mon, Aug 01, 2005 at 12:18:18PM -0400, James Bruce wrote: > > > >>The tradeoff is a realistic 4.4% power savings vs a 300% increase in > > > >>the minimum sleep period. A user will see zero power savings if they > > > >>have a USB mouse (probably 99% of desktops). On top of that, we can > > > > > > > > > > Most laptops (including mine, a Thinkpad T40) use a PS/2 mouse. So in > > > > the places where power consumption savins matters most, it's usually > > > > quite possible to function without needing any USB devices. The 90% > > > > figure isn't at all right; in fact, it may be that over 90% of the > > > > laptops still use PS/2 mice and keyboards. > > > > > > Yes, laptops are mostly PS/2, which is why I only claimed a statistic > > > for desktops. Desktops pretty much all use USB mice now. If 250Hz were > > > only being sold as an option for laptops, we could leave it at that, yet > > > its being pushed as a default that's "good for everyone". For desktops > > > this is not currently true at all. By the time USB is fixed to do power > > > saving, we'll probably have a working tick-skipping patch which makes > > > the whole HZ argument moot. > > > > Most new laptops are moving away from PS/2 ports, for example my > > shining (literally) new Acer Ferrari 4005 only has USB2 ports for mice > > and keyboard inputs (unless in the optional pcie docking station maybe). > > So my suggestion would be to fix USB power management. > > > > You are talking about external ports. I am pretty sure that installed > keyboard and touchpad (or whattever pointing device it has) are plain > old PS/2. Well, yes.. But as I _never_ use the touchpad, it is quite necessary to keep USB enabled for me at any time as an external PS2 mouse is not possible. -HK - 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/
Re: Power consumption HZ100, HZ250, HZ1000: new numbers
On Wed, 2005-08-03 at 08:57 -0500, Dmitry Torokhov wrote: On 8/3/05, Hans Kristian Rosbach [EMAIL PROTECTED] wrote: On Tue, 2005-08-02 at 00:50 -0400, James Bruce wrote: Theodore Ts'o wrote: On Mon, Aug 01, 2005 at 12:18:18PM -0400, James Bruce wrote: The tradeoff is a realistic 4.4% power savings vs a 300% increase in the minimum sleep period. A user will see zero power savings if they have a USB mouse (probably 99% of desktops). On top of that, we can Most laptops (including mine, a Thinkpad T40) use a PS/2 mouse. So in the places where power consumption savins matters most, it's usually quite possible to function without needing any USB devices. The 90% figure isn't at all right; in fact, it may be that over 90% of the laptops still use PS/2 mice and keyboards. Yes, laptops are mostly PS/2, which is why I only claimed a statistic for desktops. Desktops pretty much all use USB mice now. If 250Hz were only being sold as an option for laptops, we could leave it at that, yet its being pushed as a default that's good for everyone. For desktops this is not currently true at all. By the time USB is fixed to do power saving, we'll probably have a working tick-skipping patch which makes the whole HZ argument moot. Most new laptops are moving away from PS/2 ports, for example my shining (literally) new Acer Ferrari 4005 only has USB2 ports for mice and keyboard inputs (unless in the optional pcie docking station maybe). So my suggestion would be to fix USB power management. You are talking about external ports. I am pretty sure that installed keyboard and touchpad (or whattever pointing device it has) are plain old PS/2. Well, yes.. But as I _never_ use the touchpad, it is quite necessary to keep USB enabled for me at any time as an external PS2 mouse is not possible. -HK - 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/
Re: Power consumption HZ100, HZ250, HZ1000: new numbers
On Tue, 2005-08-02 at 00:50 -0400, James Bruce wrote: > Theodore Ts'o wrote: > > On Mon, Aug 01, 2005 at 12:18:18PM -0400, James Bruce wrote: > >>The tradeoff is a realistic 4.4% power savings vs a 300% increase in > >>the minimum sleep period. A user will see zero power savings if they > >>have a USB mouse (probably 99% of desktops). On top of that, we can > > > > Most laptops (including mine, a Thinkpad T40) use a PS/2 mouse. So in > > the places where power consumption savins matters most, it's usually > > quite possible to function without needing any USB devices. The 90% > > figure isn't at all right; in fact, it may be that over 90% of the > > laptops still use PS/2 mice and keyboards. > > Yes, laptops are mostly PS/2, which is why I only claimed a statistic > for desktops. Desktops pretty much all use USB mice now. If 250Hz were > only being sold as an option for laptops, we could leave it at that, yet > its being pushed as a default that's "good for everyone". For desktops > this is not currently true at all. By the time USB is fixed to do power > saving, we'll probably have a working tick-skipping patch which makes > the whole HZ argument moot. Most new laptops are moving away from PS/2 ports, for example my shining (literally) new Acer Ferrari 4005 only has USB2 ports for mice and keyboard inputs (unless in the optional pcie docking station maybe). So my suggestion would be to fix USB power management. The mouse that comes with the ferrari 4005 is actually a bluetooth mouse, but for some reason it is the worst thing I've ever used. So, what I'm currently using is a usb -> ps/2 converter. I can't imagine this to be any good for power consumption at all. (OT:Bad mouse) -It will overcharge battery so the whole mouse becomes HOT -Occasionally it will stop working for ~5sec -The optical sensor takes a while to focus on the pad when lifted and put down again. BTW: The laptop itself is _really_ good, just the mouse is a total failure. -HK - 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/
Re: Power consumption HZ100, HZ250, HZ1000: new numbers
On Tue, 2005-08-02 at 00:50 -0400, James Bruce wrote: Theodore Ts'o wrote: On Mon, Aug 01, 2005 at 12:18:18PM -0400, James Bruce wrote: The tradeoff is a realistic 4.4% power savings vs a 300% increase in the minimum sleep period. A user will see zero power savings if they have a USB mouse (probably 99% of desktops). On top of that, we can Most laptops (including mine, a Thinkpad T40) use a PS/2 mouse. So in the places where power consumption savins matters most, it's usually quite possible to function without needing any USB devices. The 90% figure isn't at all right; in fact, it may be that over 90% of the laptops still use PS/2 mice and keyboards. Yes, laptops are mostly PS/2, which is why I only claimed a statistic for desktops. Desktops pretty much all use USB mice now. If 250Hz were only being sold as an option for laptops, we could leave it at that, yet its being pushed as a default that's good for everyone. For desktops this is not currently true at all. By the time USB is fixed to do power saving, we'll probably have a working tick-skipping patch which makes the whole HZ argument moot. Most new laptops are moving away from PS/2 ports, for example my shining (literally) new Acer Ferrari 4005 only has USB2 ports for mice and keyboard inputs (unless in the optional pcie docking station maybe). So my suggestion would be to fix USB power management. The mouse that comes with the ferrari 4005 is actually a bluetooth mouse, but for some reason it is the worst thing I've ever used. So, what I'm currently using is a usb - ps/2 converter. I can't imagine this to be any good for power consumption at all. (OT:Bad mouse) -It will overcharge battery so the whole mouse becomes HOT -Occasionally it will stop working for ~5sec -The optical sensor takes a while to focus on the pad when lifted and put down again. BTW: The laptop itself is _really_ good, just the mouse is a total failure. -HK - 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/
