From: LIN Q. <nlv...@na...> - 2007-06-29 09:44:22
|
hi, I just found someone discussed this before in the archive of mailing list. Does anyone have some knowledge or prove that the kernel had already executes some kind of idle instruction to reduces power usage? My gumstix consumes 0.18-0.22mA when doing nothing(wifi off). LIN |
From: Robert S. <rsp...@gm...> - 2007-06-29 10:31:47
|
On 29/06/07, LIN QIU <nlv...@na...> wrote: > I just found someone discussed this before in the archive of mailing > list. Does anyone have some knowledge or prove that the kernel had > already executes some kind of idle instruction to reduces power usage? > My gumstix consumes 0.18-0.22mA when doing nothing(wifi off). That's quite surprising, considering the refresh current for the RAM is ~5mA. What type of Gumstix are you using? Rob |
Re: [Gumstix-users] The kernel already executes some kind of
idleinstruction to reduces power usage?
From: Toner, B. <ben...@ro...> - 2007-06-29 10:40:55
|
The kernel has a mode for active control of the clock speed to provide powe= r management, but it is not set on as a default. I don't know if enabling it will work on this architecture.. maybe someone = else knows? Ben -----Original Message----- From: gum...@li... on behalf of Robert Spant= on Sent: Fri 29/06/2007 11:31 To: General mailing list for gumstix users. Subject: Re: [Gumstix-users] The kernel already executes some kind of idlei= nstruction to reduces power usage? =20 On 29/06/07, LIN QIU <nlv...@na...> wrote: > I just found someone discussed this before in the archive of mailing > list. Does anyone have some knowledge or prove that the kernel had > already executes some kind of idle instruction to reduces power usage? > My gumstix consumes 0.18-0.22mA when doing nothing(wifi off). That's quite surprising, considering the refresh current for the RAM is ~5mA. What type of Gumstix are you using? Rob ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ gumstix-users mailing list gum...@li... https://lists.sourceforge.net/lists/listinfo/gumstix-users --=20 Roke Manor Research Ltd, Romsey, Hampshire, SO51 0ZN, United Kingdom A Siemens company Registered in England & Wales at: Siemens House, Oldbury, Bracknell Berks RG12 8FZ. Number 267550 ------------------------------------------------------------------------ Visit our website at www.roke.co.uk ------------------------------------------------------------------------ The information contained in this e-mail and any attachments is proprietary to Roke Manor Research Ltd and must not be passed to any third party without permission. This communication is for information only and shall not create or change any contractual relationship. ------------------------------------------------------------------------ Please consider the environment before printing this email |
From: Dave H. <dhy...@gm...> - 2007-06-29 13:55:23
|
HI Lin, > I just found someone discussed this before in the archive of mailing > list. Does anyone have some knowledge or prove that the kernel had > already executes some kind of idle instruction to reduces power usage? > My gumstix consumes 0.18-0.22mA when doing nothing(wifi off). That seems a little low. Maybe you meant 0.18 - 0.22 A which would be 180 to 220 mA, which is more in line with what I would expect. The idle process is defined by the function cpu_idle, which can be found in arch/arm/process.c The default idle routine is called "default_idle" and it calls arch_idle, which is just a wrapper for cpu_do_idle, which in turn is a macro for cpu_xscale_do_idle, which does this: /* * cpu_xscale_do_idle() * * Cause the processor to idle * * For now we do nothing but go to idle mode for every case * * XScale supports clock switching, but using idle mode support * allows external hardware to react to system state changes. */ .align 5 ENTRY(cpu_xscale_do_idle) mov r0, #1 mcr p14, 0, r0, c7, c0, 0 @ Go to IDLE mov pc, lr -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |
From: Craig H. <cr...@gu...> - 2007-06-29 14:49:19
|
~200mA does seem quite high if it's truly idling. I suspect you actually have a process which is running. Have you tried running top to see if things really are idle? C On Jun 29, 2007, at 6:55 AM, Dave Hylands wrote: > HI Lin, > >> I just found someone discussed this before in the archive of mailing >> list. Does anyone have some knowledge or prove that the kernel had >> already executes some kind of idle instruction to reduces power >> usage? >> My gumstix consumes 0.18-0.22mA when doing nothing(wifi off). > > That seems a little low. Maybe you meant 0.18 - 0.22 A which would be > 180 to 220 mA, which is more in line with what I would expect. > > The idle process is defined by the function cpu_idle, which can be > found in arch/arm/process.c > > The default idle routine is called "default_idle" and it calls > arch_idle, which is just a wrapper for cpu_do_idle, which in turn is a > macro for cpu_xscale_do_idle, which does this: > > /* > * cpu_xscale_do_idle() > * > * Cause the processor to idle > * > * For now we do nothing but go to idle mode for every case > * > * XScale supports clock switching, but using idle mode support > * allows external hardware to react to system state changes. > */ > .align 5 > > ENTRY(cpu_xscale_do_idle) > mov r0, #1 > mcr p14, 0, r0, c7, c0, 0 @ Go to IDLE > mov pc, lr > > -- > Dave Hylands > Vancouver, BC, Canada > http://www.DaveHylands.com/ > > ---------------------------------------------------------------------- > --- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users |