Measuring time in range of microseconds.

Measuring time in range of microseconds.

[Sathishkumar Duraisamy]

Hi,

I am writing a module to measure time taken between two events. I have
to measure time in microseconds. Some articles says about High
resolution timers. As per the article
http://elinux.org/High_Resolution_Timers, I read cat /proc/timer_list
which says 10000000ns as resolution ( which is 10ms). I think with
this resolution I cannot measure in the range of microseconds. I
couldn't able to find support for HR timer in kernel menuconfig.

I am using kernel 2.6.36.2. Can you please help me to, "How do enable
this timer. Or is there any other means to measure time or simply I
have to use the timer hardware directly?"

-- 
With Thanks,
Sathishkumar D
http://flowersopenlab.weebly.com/

Measuring time in range of microseconds.

[Peter Senna Tschudin]

Hi Sathishkumar,

I've used RDTSC instruction as precision timer. RDTSC measures clock cycles.

Example on:
petersenna.com/files/rdtscbench-1.0.tar.gz

More about rdtsc:
http://en.wikipedia.org/wiki/Time_Stamp_Counter
http://people.virginia.edu/~chg5w/page3/assets/MeasuringUnix.pdf

Regards,

Peter

On Tue, Dec 6, 2011 at 6:47 AM, Sathishkumar Duraisamy
<bewithsathish@gmail.com> wrote:
> Hi,
>
> I am writing a module to measure time taken between two events. I have
> to measure time in microseconds. Some articles says about High
> resolution timers. As per the article
> http://elinux.org/High_Resolution_Timers, I read cat /proc/timer_list
> which says 10000000ns as resolution ( which is 10ms). I think with
> this resolution I cannot measure in the range of microseconds. I
> couldn't able to find support for HR timer in kernel menuconfig.
>
> I am using kernel 2.6.36.2. Can you please help me to, "How do enable
> this timer. Or is there any other means to measure time or simply I
> have to use the timer hardware directly?"
>
> --
> With Thanks,
> Sathishkumar D
> http://flowersopenlab.weebly.com/
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



-- 
Peter Senna Tschudin
peter.senna at gmail.com
gpg id: 48274C36

Measuring time in range of microseconds.

[Sathishkumar Duraisamy]

Hi Peter,

Thanks for rdtsc. But I looking to measure time inside Linux Kernel
Module in ARM architecture.

-- 
Regards,
Sathishkumar D
http://flowersopenlab.weebly.com/

Measuring time in range of microseconds.

[Peter Senna Tschudin]

Hi Sathishkumar,

rdtsc is x86 specific... Sorry.

But there are other options.

Compares rdtsc with hpet:
http://aufather.wordpress.com/2010/09/08/high-performance-time-measuremen-in-linux/

Other reference about timers:
http://the-b.org/Linux_timers

I'm not sure if HPET works on ARM.

[]'s

Peter

On Tue, Dec 6, 2011 at 9:06 AM, Sathishkumar Duraisamy
<bewithsathish@gmail.com> wrote:
> Hi Peter,
>
> Thanks for rdtsc. But I looking to measure time inside Linux Kernel
> Module in ARM architecture.
>
> --
> Regards,
> Sathishkumar D
> http://flowersopenlab.weebly.com/



-- 
Peter Senna Tschudin
peter.senna at gmail.com
gpg id: 48274C36

Measuring time in range of microseconds.

[Fredrick]

I think if the specific ARM platform you are working supports a oneshot 
clock_device, you would get the high res timer support.

You can check for clock_devices defined in your platform having feature 
- CLOCK_EVT_FEAT_ONESHOT.

-Fredrick

On 12/06/2011 03:17 AM, Peter Senna Tschudin wrote:
> Hi Sathishkumar,
>
> rdtsc is x86 specific... Sorry.
>
> But there are other options.
>
> Compares rdtsc with hpet:
> http://aufather.wordpress.com/2010/09/08/high-performance-time-measuremen-in-linux/
>
> Other reference about timers:
> http://the-b.org/Linux_timers
>
> I'm not sure if HPET works on ARM.
>
> []'s
>
> Peter
>
> On Tue, Dec 6, 2011 at 9:06 AM, Sathishkumar Duraisamy
> <bewithsathish@gmail.com>  wrote:
>> Hi Peter,
>>
>> Thanks for rdtsc. But I looking to measure time inside Linux Kernel
>> Module in ARM architecture.
>>
>> --
>> Regards,
>> Sathishkumar D
>> http://flowersopenlab.weebly.com/
>
>
>

Measuring time in range of microseconds.

[Sathishkumar Duraisamy]

Hi Fredrick,

On Wed, Dec 7, 2011 at 8:12 AM, Fredrick <fjohnber@zoho.com> wrote:
> I think if the specific ARM platform you are working supports a oneshot
> clock_device, you would get the high res timer support.
>
> You can check for clock_devices defined in your platform having feature -
> CLOCK_EVT_FEAT_ONESHOT.

I have been working on s3c6410 SOC. As per kconfig file, currently for
2.6.36, my platform doesn't support these dependencies.  I have to
check with recent kernels.

"config HIGH_RES_TIMERS
	bool "High Resolution Timer Support"
	depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
	select TICK_ONESHOT
	help
	  This option enables high resolution timer support. If your
	  hardware is not capable then this option only increases
	  the size of the kernel image."

-- 
Regards,
Sathishkumar D
http://flowersopenlab.weebly.com/

Measuring time in range of microseconds.

[RKK]

Hello Satish,


On Wed, Dec 7, 2011 at 12:41 PM, Sathishkumar Duraisamy
<bewithsathish@gmail.com> wrote:
> Hi Fredrick,
>
> On Wed, Dec 7, 2011 at 8:12 AM, Fredrick <fjohnber@zoho.com> wrote:
>> I think if the specific ARM platform you are working supports a oneshot
>> clock_device, you would get the high res timer support.
>>
>> You can check for clock_devices defined in your platform having feature -
>> CLOCK_EVT_FEAT_ONESHOT.
>
My guess is that u want to measure the time taken to execute a
function in microseconds.
something like
start_time
YOUR_FUNCTION
end_time

for this i use  something like this declare
struct timeval tv in your function

and insert printk statements before and after calling to your function

do_gettimeofday(&tv);
 printk ("Before  %s (): Sec = %d    micro Sec = %d\n", __FUNCTION__,
tv.tv_sec, tv.tv_usec);
call_to_your_function(();
 printk ("After %s (): Sec = %d    micro Sec = %d\n", __FUNCTION__,
tv.tv_sec, tv.tv_usec);

-- 
Warm Regards,
Ravi .
"I don't Know is not a excuse , its an opportunity."

Measuring time in range of microseconds.

[Sathishkumar Duraisamy]

Hi

On Wed, Dec 7, 2011 at 3:10 PM, RKK <kulkarni.ravi4@gmail.com> wrote:
> Hello Satish,
>
>
> On Wed, Dec 7, 2011 at 12:41 PM, Sathishkumar Duraisamy
> <bewithsathish@gmail.com> wrote:
>> Hi Fredrick,
>>
>> On Wed, Dec 7, 2011 at 8:12 AM, Fredrick <fjohnber@zoho.com> wrote:
>>> I think if the specific ARM platform you are working supports a oneshot
>>> clock_device, you would get the high res timer support.
>>>
>>> You can check for clock_devices defined in your platform having feature -
>>> CLOCK_EVT_FEAT_ONESHOT.
>>
> My guess is that u want to measure the time taken to execute a
> function in microseconds.
> something like
> start_time
> YOUR_FUNCTION
> end_time

Sorry. I want to measure external pulse on a GPIO pin.

-- 
Regards,
Sathishkumar D
http://flowersopenlab.weebly.com/