RE: DSP Cycles measurement on DM6467
Prasad,
The high resolution clock that DSP/BIOS uses on 64x+ architecture is called the
time-stamp counter (TSC), which is part of the 64x+ Megamodule. It's a 64-bit
counter consisting of two registers, TSCH and TSCL, that operate at CPU/1.
When you call CLK_gethtime it reads TSCL.
By default TSC does not count. The software needs to do a dummy write to TSCL
to make it start. In my experience that is always done automatically by BIOS.
Perhaps in your BIOS configuration something turned it off. Make sure that
bios.CLK.ENABLEHTIME = 1 in your tcf. That is the default value, so unless
someone explicitly set it to 0 somewhere it should be on. That seems the most
likely config option to affect this.
Once you enable that option you should see CLK_cpuCyclesPerHtime return 1 since
the TSC counts at CPU/1.
Brad
-Original Message-
From: davinci-linux-open-source-boun...@linux.davincidsp.com
[mailto:davinci-linux-open-source-boun...@linux.davincidsp.com] On Behalf Of
Joshi, Prasad
Sent: Friday, April 17, 2009 4:21 AM
To: davinci-linux-open-source@linux.davincidsp.com
Subject: DSP Cycles measurement on DM6467
I want to measure DSP cycles consumed in a function.
what i am doing is as follows.
time1 = CLK_gethtime();
function()
{
//some code
}
time2 = CLK_gethtime();
DSP_Cycles = (time2- time1) * (CLK_cpuCyclesPerHtime())
When i print DSP_Cycles, it gives zero.
Then i tried printing (CLK_cpuCyclesPerHtime()) directly & found that it is
returning zero.
CLK_cpuCyclesPerHtime() returns a Float value.
I tried printing it with %f, %32.3g %ld (After type proper casting), but every
time it is prinintg zero.
I have added all header files (bios/include/log.h, bios/include/clk.h,
bios/include/gbl.h) & CLK is initialised too.
Can anyone tell where am I making mistake?
Thanks & Regards
Prasad V. Joshi
Texas Instruments
Off: 080-25099173
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RE: DSP Cycles measurement on DM6467
Before accessing the TSC registers, you need to enable them by calling:
TSC_enable();
To get the DSP cycles, the best option is to use TSC_read(). This returns a 64
bit unsigned int containing the value of both TSCH and TSCL registers.
Regards,
Anand
-Original Message-
From: davinci-linux-open-source-boun...@linux.davincidsp.com
[mailto:davinci-linux-open-source-boun...@linux.davincidsp.com] On Behalf Of
Griffis, Brad
Sent: Friday, April 17, 2009 10:53 PM
To: Joshi, Prasad; davinci-linux-open-source@linux.davincidsp.com
Subject: RE: DSP Cycles measurement on DM6467
Prasad,
The high resolution clock that DSP/BIOS uses on 64x+ architecture is called the
time-stamp counter (TSC), which is part of the 64x+ Megamodule. It's a 64-bit
counter consisting of two registers, TSCH and TSCL, that operate at CPU/1.
When you call CLK_gethtime it reads TSCL.
By default TSC does not count. The software needs to do a dummy write to TSCL
to make it start. In my experience that is always done automatically by BIOS.
Perhaps in your BIOS configuration something turned it off. Make sure that
bios.CLK.ENABLEHTIME = 1 in your tcf. That is the default value, so unless
someone explicitly set it to 0 somewhere it should be on. That seems the most
likely config option to affect this.
Once you enable that option you should see CLK_cpuCyclesPerHtime return 1 since
the TSC counts at CPU/1.
Brad
-Original Message-
From: davinci-linux-open-source-boun...@linux.davincidsp.com
[mailto:davinci-linux-open-source-boun...@linux.davincidsp.com] On Behalf Of
Joshi, Prasad
Sent: Friday, April 17, 2009 4:21 AM
To: davinci-linux-open-source@linux.davincidsp.com
Subject: DSP Cycles measurement on DM6467
I want to measure DSP cycles consumed in a function.
what i am doing is as follows.
time1 = CLK_gethtime();
function()
{
//some code
}
time2 = CLK_gethtime();
DSP_Cycles = (time2- time1) * (CLK_cpuCyclesPerHtime())
When i print DSP_Cycles, it gives zero.
Then i tried printing (CLK_cpuCyclesPerHtime()) directly & found that it is
returning zero.
CLK_cpuCyclesPerHtime() returns a Float value.
I tried printing it with %f, %32.3g %ld (After type proper casting), but every
time it is prinintg zero.
I have added all header files (bios/include/log.h, bios/include/clk.h,
bios/include/gbl.h) & CLK is initialised too.
Can anyone tell where am I making mistake?
Thanks & Regards
Prasad V. Joshi
Texas Instruments
Off: 080-25099173
___
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Davinci-linux-open-source@linux.davincidsp.com
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RE: DSP Cycles measurement on DM6467
On Mon, 2009-04-20 at 11:08 +0530, Balagopalakrishnan, Anand wrote: > Before accessing the TSC registers, you need to enable them by > calling: > TSC_enable(); Which timer does TSC_enable initialize? Would that interfere with ARM or we don't really care about ARM for this test? > > To get the DSP cycles, the best option is to use TSC_read(). This > returns a 64 bit unsigned int containing the value of both TSCH and > TSCL registers. > > Regards, > Anand > ___ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
RE: DSP Cycles measurement on DM6467
The TSC_enable initialize the 32 bit registers - TSCL & TSCH. They are used only on DSP. Regards, Anand -Original Message- From: Steve Chen [mailto:sc...@mvista.com] Sent: Monday, April 20, 2009 5:22 PM To: Balagopalakrishnan, Anand Cc: Griffis, Brad; Joshi, Prasad; davinci-linux-open-source@linux.davincidsp.com Subject: RE: DSP Cycles measurement on DM6467 On Mon, 2009-04-20 at 11:08 +0530, Balagopalakrishnan, Anand wrote: > Before accessing the TSC registers, you need to enable them by > calling: > TSC_enable(); Which timer does TSC_enable initialize? Would that interfere with ARM or we don't really care about ARM for this test? > > To get the DSP cycles, the best option is to use TSC_read(). This > returns a 64 bit unsigned int containing the value of both TSCH and > TSCL registers. > > Regards, > Anand > ___ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
