4 ms·

Soooo the Linux kernel now compiles in 15.6 seconds. Jeebus I feel old...

sp332 9y ago
I was about to point out that it compiled in 4.8 seconds back in 2002 http://es.tldp.org/Presentaciones/200211hispalinux/blanchard/talk_2.html http://es.tldp.org/Presentaciones/200211hispalinux/blanchard... But then I remembered that it was only 4 million lines of code back then (v2.5.x) and now it's 18 million! https://www.linuxcounter.net/statistics/kernel https://www.linuxcounter.net/statistics/kernel (Edit: fixed second link)
- hyperbovine 9y ago
  I haven't compiled it since the days of Slackware but it took at least on hour on my Pentium 90. (Then I discovered Debian.)
  - claudiug 9y ago
    Remember gentoo Linux
    - quickben 9y ago
      Actually considering it for the next build. 16 amd core CPU. Probably 4 machines to crunch on something in the next few years. These are awesome times we live in.
    - peller 9y ago
      I'll admit the endless compiling was often torturous, but I have the Gentoo docs to thank for most of what I know about the innards of Linux and operating systems. Bet I'm not alone in judging the time spent worth it :)
      - thomasmeeks 9y ago
        My time in Gentoo was absolutely worth it for the same reasons. There are dozens of us! Dozens! I still recommend it to people who are serious about diving into Linux.
      - c3833174 9y ago
        I'd say I learned more by playing around with Slackware, but Gentoo provides all those nice tools to mantain a consistent system.
- stingraycharles 9y ago
  There used to be a long running joke (I think perhaps Linus even coined it?) that the kernel codebase grew about as fast as CPU performance improved. I guess that died around the time AMD released their dual core CPUs..
  - ethbro 9y ago
    It seems reasonable, considering anyone working on it enough to need to recompile would have a minimum change time correlated with compilation time. (Incremental compilation aside)
    - seanp2k2 9y ago
      Going to get a cup of coffee takes the same amount of time as it did 15 years ago, so devs still need a compile time which is roughly equivalent. 15 seconds would be much too fast, for example.
  - amiga-workbench 9y ago
    "What Intel giveth, Microsoft taketh away"
- derefr 9y ago
  Is that an apples-to-apples comparison (either both monolith or both all-modules kernels, both with all drivers enabled?) I recall, back in the long long ago, running through `make menuconfig` and disabling what I didn't need to get a smaller kernel + shorter build-times.
  - sp332 9y ago
    No, I'm sure lots of things have changed. More of the code would be using C99 semantics now, and I have no idea how GCC would have improved or regressed since then. It's possible that it's trading improved runtime performance on ever-more complex hardware for longer compile times.
    - zbobet2012 9y ago
      The kernel is still c89.
      - sp332 9y ago
        I see that gnu89 is the default, to avoid compatibility problems with older code, but does that mean there is no code in the kernel which requires gnu99? I saw some work was done to make the whole kernel gnu11 compatible as well.
        fahadkhan 9y ago
        https://stackoverflow.com/questions/20600497/which-c-version-is-used-in-the-linux-kernel https://stackoverflow.com/questions/20600497/which-c-version...
        sp332 9y ago
        Right, but I was too lazy to do my own analysis and just extrapolated from that 2013 post to guess that the number is higher now.
- mrb 9y ago
  The difference being of course that this 4.8-second compile in 2002 was done on an IBM p690 which cost half a million dollars. Whereas the 15.6-second compile was done on the EPYC 7601 which is only $4k for the CPU, ~$6k for a whole machine. $6k vs $500k... Let that sink in :)
  - dis-sys 9y ago
    did they fix the random crash issue when running gcc? https://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Compiler-Issues https://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Co...
    - pulse7 9y ago
      AMD Forum Thread: https://community.amd.com/thread/215773 https://community.amd.com/thread/215773 Last response from AMD: "The vast majority of users using Ryzen for Linux code and development have reported very positive results. ... A small number of users have reported some isolated issues and conflicting observations. AMD is working with users individually to understand and resolve these issues."
    - 0xcde4c3db 9y ago
      I doubt there's any single root cause here. "I get crashes when running big compiles" is a classic symptom of hardware that is almost, but not quite, stable. This can be due to power delivery problems, thermals, marginal RAM, overclocks, faulty CPU (yeah, it happens sometimes) and so on.
agumonkey 9y ago
Run tccboot iso, you'll have your 15minutes of youthful fun https://bellard.org/tcc/tccboot.html https://bellard.org/tcc/tccboot.html
setq 9y ago
I still remember doing a make world on FreeBSD on a 75MHz Pentium. Went out for the night and it was still going when the hangover wore off the following afternoon. This was mainly because it spent most of it's time swapping.
Symmetry 9y ago
The browser is the new OS and the compile times prove it.
ekianjo 9y ago
some of the reduction is not just hardware related if i remember correctly. Compilers have improved as well.

I was about to point out that it compiled in 4.8 seconds back in 2002 http://es.tldp.org/Presentaciones/200211hispalinux/blanchard/talk_2.html http://es.tldp.org/Presentaciones/200211hispalinux/blanchard... But then I remembered that it was only 4 million lines of code back then (v2.5.x) and now it's 18 million! https://www.linuxcounter.net/statistics/kernel https://www.linuxcounter.net/statistics/kernel (Edit: fixed second link)

hyperbovine 9y ago
I haven't compiled it since the days of Slackware but it took at least on hour on my Pentium 90. (Then I discovered Debian.)
- claudiug 9y ago
  Remember gentoo Linux
  - quickben 9y ago
    Actually considering it for the next build. 16 amd core CPU. Probably 4 machines to crunch on something in the next few years. These are awesome times we live in.
  - peller 9y ago
    I'll admit the endless compiling was often torturous, but I have the Gentoo docs to thank for most of what I know about the innards of Linux and operating systems. Bet I'm not alone in judging the time spent worth it :)
    - thomasmeeks 9y ago
      My time in Gentoo was absolutely worth it for the same reasons. There are dozens of us! Dozens! I still recommend it to people who are serious about diving into Linux.
    - c3833174 9y ago
      I'd say I learned more by playing around with Slackware, but Gentoo provides all those nice tools to mantain a consistent system.
stingraycharles 9y ago
There used to be a long running joke (I think perhaps Linus even coined it?) that the kernel codebase grew about as fast as CPU performance improved. I guess that died around the time AMD released their dual core CPUs..
- ethbro 9y ago
  It seems reasonable, considering anyone working on it enough to need to recompile would have a minimum change time correlated with compilation time. (Incremental compilation aside)
  - seanp2k2 9y ago
    Going to get a cup of coffee takes the same amount of time as it did 15 years ago, so devs still need a compile time which is roughly equivalent. 15 seconds would be much too fast, for example.
- amiga-workbench 9y ago
  "What Intel giveth, Microsoft taketh away"
derefr 9y ago
Is that an apples-to-apples comparison (either both monolith or both all-modules kernels, both with all drivers enabled?) I recall, back in the long long ago, running through `make menuconfig` and disabling what I didn't need to get a smaller kernel + shorter build-times.
- sp332 9y ago
  No, I'm sure lots of things have changed. More of the code would be using C99 semantics now, and I have no idea how GCC would have improved or regressed since then. It's possible that it's trading improved runtime performance on ever-more complex hardware for longer compile times.
  - zbobet2012 9y ago
    The kernel is still c89.
    - sp332 9y ago
      I see that gnu89 is the default, to avoid compatibility problems with older code, but does that mean there is no code in the kernel which requires gnu99? I saw some work was done to make the whole kernel gnu11 compatible as well.
      - fahadkhan 9y ago
        https://stackoverflow.com/questions/20600497/which-c-version-is-used-in-the-linux-kernel https://stackoverflow.com/questions/20600497/which-c-version...
        sp332 9y ago
        Right, but I was too lazy to do my own analysis and just extrapolated from that 2013 post to guess that the number is higher now.
mrb 9y ago
The difference being of course that this 4.8-second compile in 2002 was done on an IBM p690 which cost half a million dollars. Whereas the 15.6-second compile was done on the EPYC 7601 which is only $4k for the CPU, ~$6k for a whole machine. $6k vs $500k... Let that sink in :)
- dis-sys 9y ago
  did they fix the random crash issue when running gcc? https://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Compiler-Issues https://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Co...
  - pulse7 9y ago
    AMD Forum Thread: https://community.amd.com/thread/215773 https://community.amd.com/thread/215773 Last response from AMD: "The vast majority of users using Ryzen for Linux code and development have reported very positive results. ... A small number of users have reported some isolated issues and conflicting observations. AMD is working with users individually to understand and resolve these issues."
  - 0xcde4c3db 9y ago
    I doubt there's any single root cause here. "I get crashes when running big compiles" is a classic symptom of hardware that is almost, but not quite, stable. This can be due to power delivery problems, thermals, marginal RAM, overclocks, faulty CPU (yeah, it happens sometimes) and so on.

agumonkey 9y ago

Run tccboot iso, you'll have your 15minutes of youthful fun https://bellard.org/tcc/tccboot.html https://bellard.org/tcc/tccboot.html

setq 9y ago

I still remember doing a make world on FreeBSD on a 75MHz Pentium. Went out for the night and it was still going when the hangover wore off the following afternoon. This was mainly because it spent most of it's time swapping.

Symmetry 9y ago

The browser is the new OS and the compile times prove it.

ekianjo 9y ago

some of the reduction is not just hardware related if i remember correctly. Compilers have improved as well.