Delay in running interrupt service routine

Hi 

Trying to service ADC data ready signal with an interrupt service routine it has about 4 micro second delay which is around 1200 CPU cycles which is not acceptable in my case.

I am working with OMAPL138 StarterWare 1_10_04_01 and CSS 5.4.0.00091 and INT4.

I did not have  such a problem with CSS 3.3 and DSP/BIOS. There was a option there to disable dispatcher for interrupt (which may be relevant) and I did not find similar option with CCS 5.

Any idea?

Thanks.