can you anyone tell what the linux patch is? I want to install a real time kernel, so to compile the kernel first I need to add the downloaded real time patch to it :
patch -p1 < patch-rt-version
but what about the kernel's own patch? as I've seen when I download the kernel from kernel.org, the kernels patches are also in the same kernel folder.
Don't put in patches unless you know why you're putting them in; if you didn't want them, they're not for you. Patches are simply a set of modifications to the kernel source.
Lots of kernel patches are available on kernel.org for convenience; they let you turn version 1.2.3 into version 1.2.4 by downloading a tiny text file instead of a 60 megabyte archive. patches also let you see exactly what changed.