[SOLVED] More than one hour to compile kernel

[MH]

For some reason compile times have tripled on my system. The first time I compiled a kernel (4.9.30) it took ~26 min. The last time it took more than one hour. The kernel source is unchanged (I use it for benchmarking/burn-in), as is kernel configuration. The script I run does a "make clean" before each build.

The only changes to the system (AMD Ryzen 1200 @ 3.5GHz running Buster) have been software updates. I know GCC has been updated, so I'm wondering if that's the cause? Haven't found anything related searching the Internet. I thought maybe my CPU was throttling down, but when I checked the temps they were below 60C. Other benchmarks show no change in performance.

[stevepusser]

Are you doing a parallel build or single-threaded? The Debian kernel takes about that long to recompile on my dual core 4-threaded i5, but then it takes another couple hours to convert and build the documentation packages. The Liquorix kernel package takes a little longer for the builds for amd64, since it's building more drivers, and the 32-bit build twice as long since it's building a PAE and non-PAE kernel---no docs with Liquorix.

I suppose you can check to see many of your cores are being utilized for the build.

[MH]

Are you doing a parallel build or single-threaded? The Debian kernel takes about that long to recompile on my dual core 4-threaded i5, but then it takes another couple hours to convert and build the documentation packages. The Liquorix kernel package takes a little longer for the builds for amd64, since it's building more drivers, and the 32-bit build twice as long since it's building a PAE and non-PAE kernel---no docs with Liquorix.

I suppose you can check to see many of your cores are being utilized for the build.

I'm using all four threads, though time is not the issue. Time delta is the issue. Same hardware, same kernel, same configuration, drastically different build times. There's been another GCC update, so maybe I'll try another compile and see what happens.

[MH]

Looks like the problem was with GCC. I tried compiling a kernel again after a recent update and the compile time dropped to ~25 minutes. Either there was a problem with the previous version, or playing solitaire while I did the earlier compile caused it to take 3x longer. Since solitaire takes less than 3% CPU, that seems unlikely.