Executable built using gcc runs slower than one built using CCS

Vineeth Balan

Hi ,

I have noticed considerable difference in the performance of a StarterWare USB application when I building with StarterWare GCC tool chain and when built using the CCS compiler .

In order to set the context , I am using the usb_host_msc example which essentially supports reads and writes to devices like hard drives. My test setup is as follows

Platform : AM335x - only data caches are on.

Code base : StarterWare release 7 package modified to do RAW reads and writes. By RAM i mean bypassing the file system

Device : WD external hard drive

Using GCC I obtanied a READ speed of 4MB/s and the same code base when compiler with CCS compiler returned 16MB/s.With GCC it is set optimization level 2 . In case

anyone needs a list of compiler settings , i would gladly post them.

Initially it was reasoned that the memcopy or similar library supplied functions would be affecting the performance of GCC executable. But this reason does not seem to hold as the write speed obtained using both the tool chains was very similar (close to 16 MB/s) .

Has any body seen something similar ?

Thanks in advance

Vineeth

over 13 years ago

George Mock over 13 years ago

TI__Guru**** 251270 points

It is likely that the source of the performance difference is somewhere in the system configuration. We compiler experts don't know much about system configuration. I recommend you try the StarterWare forum.

Thanks and regards,

-George

Vineeth Balan over 13 years ago in reply to George Mock

TI__Intellectual 1640 points

Hi George ,

Thanks for the input. What perplexes me, is that I use the same code base , build with 2 compilers and the performance differs. By system config do you mean the clock config , cache configuration etc ? If yes then it is the same in both the cases.

George Mock over 13 years ago in reply to Vineeth Balan

TI__Guru**** 251270 points

I don't have a good definition of system configuration. In this particular case, I wonder whether all the code and data resides in the same kind of memory. That is, are the wait states, cache performance, etc all the same? Another possibility is that some peripheral is configured differently. These are all things we compiler folks don't know much about.

Thanks and regards,

-George

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Executable built using gcc runs slower than one built using CCS