How to apply patch to kernel?

I am compiling a build for a WNDR3700v1 and am trying to apply a CPU overclock patch - my understanding was that I had to place the patch file in the correct directory so that it would apply during compile.

the patch information is located here: http://luci.subsignal.org/~trondah/archive/overclock.txt
a copy of the patch is here: http://luci.subsignal.org/~trondah/archive/overclock.patch

I placed it in following location: target/linux/ar71xx/patches-4.4/overclock.patch

Is there any way to confirm if this patch has indeed been applied?
I'm thinking that it may not have been, as the router still seems quite slow- certainly not as snappy as the build I was using previously of OpenWRT which someone had compiled with this patch applied.
Also my load numbers are much higher than when I had the overclock on OpenWRT (even though I have less packages on LEDE) and the unit doesn't get as warm... all things indicate to me it's not applied.

Thanks!

You can look at the patched code in build_dir (and its subdirs...)

ls build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.47/

You can also experiment editing the patch and seeing if the kernel source gets patched. The command make target/linux/{clean,prepare} will clean/remove the kernel sources from build_dir and then unpack the original sources plus apply the kernel patches including yours:

$ make target/linux/{clean,prepare}
 make[1] target/linux/clean
 make[2] -C target/linux clean
 make[1] target/linux/prepare
 make[2] -C target/linux prepare

The overclock should also be visible in dmesg. This is from a normal WNDR3700. Your overclocked values should be higher, I think:

# dmesg | grep -i clock
[    0.000000] Clocks: CPU:680.000MHz, DDR:340.000MHz, AHB:170.000MHz, Ref:40.000MHz
[    0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 5621354254 ns
[    0.000008] sched_clock: 32 bits at 340MHz, resolution 2ns, wraps every 6316128254ns
[    0.090887] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    2.835548] clocksource: Switched to clocksource MIPS

# dmesg | grep -i bogo
[    0.007782] Calibrating delay loop... 452.19 BogoMIPS (lpj=2260992)

Thanks for the pointers. I had searched quite a bit to try find where the clock speed would be printed and couldnt find anything for MIPS based devices. But your one liner definitely worked thank you, and it appears that the patch is indeed applying.
I see this;

root@LEDE:~# dmesg | grep -i clock
[    0.000000] Clocks: CPU:800.000MHz, DDR:400.000MHz, AHB:200.000MHz, Ref:40.000MHz
[    0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 4778151116 ns
[    0.000007] sched_clock: 32 bits at 400MHz, resolution 2ns, wraps every 5368709118ns
[    0.086283] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    2.813608] clocksource: Switched to clocksource MIPS
root@LEDE:~# dmesg | grep -i bogo
[    0.006617] Calibrating delay loop... 531.66 BogoMIPS (lpj=2658304)

I will take a look around and see what is causing all the load and slowness, must be something else.