* RE: AM335x mpurate + bogomips
2013-02-21 16:36 AM335x mpurate + bogomips Mark Jackson
@ 2013-02-21 18:30 ` Hiremath, Vaibhav
2013-02-22 8:03 ` Jason Kridner
2013-02-22 16:43 ` Frank Agius
2 siblings, 0 replies; 5+ messages in thread
From: Hiremath, Vaibhav @ 2013-02-21 18:30 UTC (permalink / raw)
To: Mark Jackson, linux-omap@vger.kernel.org
> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
> owner@vger.kernel.org] On Behalf Of Mark Jackson
> Sent: Thursday, February 21, 2013 10:06 PM
> To: linux-omap@vger.kernel.org
> Subject: AM335x mpurate + bogomips
>
> Before I dig any deeper, can anyone tell me if the bootarg "mpurate" is
> meant to
> be supported for AM335x SoCs ?
>
No, certainly not. "mpurate" bootargs was supported long time back,
If you are probably using 2.6.32 based kernel from TI on top of AM37x.
> I've tried it on our custom board using 3v8, but no joy.
>
> The boot log shows:-
>
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Linux version 3.8.0-03059-g621553c-dirty (mpfj@mpfj-
> nanobone) (gcc version 4.5.4 (Buildroot 2012.11) ) #113 SMP Thu Feb 21
> 16:29:48 GMT 2013
> [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7),
> cr=10c53c7d
> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing
> instruction cache
> [ 0.000000] Machine: Generic AM33XX (Flattened Device Tree), model:
> Newflow NanoBone
> [ 0.000000] Memory policy: ECC disabled, Data cache writeback
> [ 0.000000] CPU: All CPU(s) started in SVC mode.
> [ 0.000000] AM335X ES1.0 (neon )
> ...
> [ 0.000000] Kernel command line: console=ttyO0,115200n8 mpurate=720
> root=/dev/mmcblk0p2 ro rootfstype=ext2 rootwait
> ...
> [ 0.001119] Calibrating delay loop... 364.48 BogoMIPS (lpj=1425408)
>
> I have seen other boot logs outputs [1] from other people where they
> are getting nearly double that.
>
> Looking at omap2xxx_clk_arch_init(), only ompa24xx devices are
> supported.
>
> Am I missing something obvious (like it's not yet supported !!) ?
>
I also seen same issue, and its there from long time now.
Didn't get chance to nail down this.
Does anybody know, whether Bogomips represents right value in case of OMAP??
On the other side, CPUFREQ is supported in the mainline kernel.
Thanks,
Vaibhav
> Cheers
> Mark J.
>
> [1] http://e2e.ti.com/support/embedded/linux/f/354/t/245316.aspx
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap"
> in
> the body of a message to majordomo@vger.kernel.org
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: AM335x mpurate + bogomips
2013-02-21 16:36 AM335x mpurate + bogomips Mark Jackson
2013-02-21 18:30 ` Hiremath, Vaibhav
@ 2013-02-22 8:03 ` Jason Kridner
2013-02-22 14:49 ` Nishanth Menon
2013-02-22 16:43 ` Frank Agius
2 siblings, 1 reply; 5+ messages in thread
From: Jason Kridner @ 2013-02-22 8:03 UTC (permalink / raw)
To: Mark Jackson; +Cc: linux-omap@vger.kernel.org
On Thu, Feb 21, 2013 at 11:36 AM, Mark Jackson <mpfj-list@mimc.co.uk> wrote:
> Before I dig any deeper, can anyone tell me if the bootarg "mpurate" is meant to
> be supported for AM335x SoCs ?
>
> I've tried it on our custom board using 3v8, but no joy.
>
> The boot log shows:-
>
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Linux version 3.8.0-03059-g621553c-dirty (mpfj@mpfj-nanobone) (gcc version 4.5.4 (Buildroot 2012.11) ) #113 SMP Thu Feb 21 16:29:48 GMT 2013
> [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d
> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
> [ 0.000000] Machine: Generic AM33XX (Flattened Device Tree), model: Newflow NanoBone
> [ 0.000000] Memory policy: ECC disabled, Data cache writeback
> [ 0.000000] CPU: All CPU(s) started in SVC mode.
> [ 0.000000] AM335X ES1.0 (neon )
> ...
> [ 0.000000] Kernel command line: console=ttyO0,115200n8 mpurate=720 root=/dev/mmcblk0p2 ro rootfstype=ext2 rootwait
> ...
> [ 0.001119] Calibrating delay loop... 364.48 BogoMIPS (lpj=1425408)
I don't think mpurate does anything on AM335x, though I could be
wrong---just that I've not heard of anyone using it for any purpose.
The BogoMIPS values don't seem to be very useful. I'm not sure of
their purpose, but the hopefully useful information I can offer you is
that if you are running a kernel supporting dynamic frequency scaling
on AM335x, the number tends to be lower.
>
> I have seen other boot logs outputs [1] from other people where they are getting nearly double that.
>
> Looking at omap2xxx_clk_arch_init(), only ompa24xx devices are supported.
>
> Am I missing something obvious (like it's not yet supported !!) ?
Use the cpufreq tools to determine and set the frequency.
>
> Cheers
> Mark J.
>
> [1] http://e2e.ti.com/support/embedded/linux/f/354/t/245316.aspx
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: AM335x mpurate + bogomips
2013-02-22 8:03 ` Jason Kridner
@ 2013-02-22 14:49 ` Nishanth Menon
0 siblings, 0 replies; 5+ messages in thread
From: Nishanth Menon @ 2013-02-22 14:49 UTC (permalink / raw)
To: Jason Kridner; +Cc: Mark Jackson, linux-omap@vger.kernel.org
On 02/22/2013 02:03 AM, Jason Kridner wrote:
> On Thu, Feb 21, 2013 at 11:36 AM, Mark Jackson <mpfj-list@mimc.co.uk> wrote:
>> Before I dig any deeper, can anyone tell me if the bootarg "mpurate" is meant to
>> be supported for AM335x SoCs ?
>>
>> I've tried it on our custom board using 3v8, but no joy.
>>
>> The boot log shows:-
>>
>> [ 0.000000] Booting Linux on physical CPU 0x0
>> [ 0.000000] Linux version 3.8.0-03059-g621553c-dirty (mpfj@mpfj-nanobone) (gcc version 4.5.4 (Buildroot 2012.11) ) #113 SMP Thu Feb 21 16:29:48 GMT 2013
>> [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d
>> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
>> [ 0.000000] Machine: Generic AM33XX (Flattened Device Tree), model: Newflow NanoBone
>> [ 0.000000] Memory policy: ECC disabled, Data cache writeback
>> [ 0.000000] CPU: All CPU(s) started in SVC mode.
>> [ 0.000000] AM335X ES1.0 (neon )
>> ...
>> [ 0.000000] Kernel command line: console=ttyO0,115200n8 mpurate=720 root=/dev/mmcblk0p2 ro rootfstype=ext2 rootwait
>> ...
>> [ 0.001119] Calibrating delay loop... 364.48 BogoMIPS (lpj=1425408)
>
> I don't think mpurate does anything on AM335x, though I could be
> wrong---just that I've not heard of anyone using it for any purpose.
>
> The BogoMIPS values don't seem to be very useful. I'm not sure of
> their purpose, but the hopefully useful information I can offer you is
> that if you are running a kernel supporting dynamic frequency scaling
> on AM335x, the number tends to be lower.
>
>>
>> I have seen other boot logs outputs [1] from other people where they are getting nearly double that.
>>
>> Looking at omap2xxx_clk_arch_init(), only ompa24xx devices are supported.
>>
>> Am I missing something obvious (like it's not yet supported !!) ?
>
> Use the cpufreq tools to determine and set the frequency.
Cant we just drop mpurate?
The initial trigger was to be able to boot at a known frequency -
bootloaders typically do that. having to deal with mpurate means that we
have to deal with it for *all* SoCs - which means we have to support
frequency and voltage "forced setting", including other fringe stuff
like abb, avs etc..
for example: just doing a clock setting to 1GHz is not an good idea if
bootloader booted at 300MHz without being able to do everything right
*if* it is right for the SoC.
I agree with Jason here, if we wanted to boot up kernel at a higher
frequency - do it in the bootloader.
if your bootloader is not controlled or "too ancient to be modified", do
it with cpufreq userspace utils.
at least the bootlogic will remain in the "at least predictable boot
order" of initcalls and subsystem bringup sequences without having to
deal with "exception overrides" like mpurate, which dont always work 100%.
---
Regards,
Nishanth Menon
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: AM335x mpurate + bogomips
2013-02-21 16:36 AM335x mpurate + bogomips Mark Jackson
2013-02-21 18:30 ` Hiremath, Vaibhav
2013-02-22 8:03 ` Jason Kridner
@ 2013-02-22 16:43 ` Frank Agius
2 siblings, 0 replies; 5+ messages in thread
From: Frank Agius @ 2013-02-22 16:43 UTC (permalink / raw)
Cc: linux-omap@vger.kernel.org
On 2/21/2013 11:36 AM, Mark Jackson wrote:
> Before I dig any deeper, can anyone tell me if the bootarg "mpurate" is meant to
> be supported for AM335x SoCs ?
>
> I've tried it on our custom board using 3v8, but no joy.
>
> The boot log shows:-
>
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Linux version 3.8.0-03059-g621553c-dirty (mpfj@mpfj-nanobone) (gcc version 4.5.4 (Buildroot 2012.11) ) #113 SMP Thu Feb 21 16:29:48 GMT 2013
> [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d
> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
> [ 0.000000] Machine: Generic AM33XX (Flattened Device Tree), model: Newflow NanoBone
> [ 0.000000] Memory policy: ECC disabled, Data cache writeback
> [ 0.000000] CPU: All CPU(s) started in SVC mode.
> [ 0.000000] AM335X ES1.0 (neon )
> ...
> [ 0.000000] Kernel command line: console=ttyO0,115200n8 mpurate=720 root=/dev/mmcblk0p2 ro rootfstype=ext2 rootwait
> ...
> [ 0.001119] Calibrating delay loop... 364.48 BogoMIPS (lpj=1425408)
>
> I have seen other boot logs outputs [1] from other people where they are getting nearly double that.
>
I have also observed a drop in the reported BogoMIPS value when using
the latest kernel. Previously (with a 3.5 kernel) the BogoMIPS value
was approximately equal to the CPU frequency. I finally found the reason
for the BogoMIPS change:
http://www.spinics.net/lists/arm-kernel/msg221672.html
It looks like BogoMIPS reporting changed because of the delay routine
patch introduced in 3.6. So the change in BogoMIPS is real, but should
not be a concern.
frank agius
^ permalink raw reply [flat|nested] 5+ messages in thread