On Tue, Jul 5, 2016 at 2:37 PM, Ralph Giles <gi...@mozilla.com> wrote:
> On Tue, Jul 5, 2016 at 12:12 PM, Gregory Szorc <g...@mozilla.com> wrote: > > > I recommend 2x Xeon E5-2637v4 or E5-2643v4. > > For comparison's sake, what kind of routine and clobber build times do > you see on a system like this? How much does the extra cache on Xeon > help vs something like a 4 GHz i7? > > My desktop machine is five years old, but it's still faster than my > MacBook Pro, so I've never bothered upgrading beyond newer SSDs. If > there's a substantial improvement available in build times it would be > easier to justify new hardware. > > A nop build on my desktop is 22s currently. Touching a cpp file (so > re-linking xul) is 46s. A clobber build is something like 17 minutes. > Let's put it this way: I've built on AWS c4.8xlarge instances (Xeon E5-2666 v3 with 36 vCPUs) and achieved clobber build times comparable to the best numbers the Toronto office has reported with icecc (between 3.5 and 4 minutes). That's 36 vCPUs @ 2.9-3.2/3.5GHz (base vs turbo single/all cores frequency). I don't have access to a 2xE5-2643v4 machine, but I do have access to a 2 x E5-2637v4 with 32 GB RAM and an SSD running CentOS 7 (Clang 3.4.2 + gold linker): * clobber (minus configure): 368s (6:08) * `mach build` (no-op): 24s * `mach build binaries` (no-op): 3.4s * `mach build binaries` (touch network/dns/DNS.cpp): 14.1s I'm pretty sure the clobber time would be a little faster with a newer Clang (also, GCC is generally faster than Clang). That's 8 physical cores + hyperthreading (16 reported CPUs) @ 3.5 GHz. A 2643v4 would be 12 physical cores @ 3.4 GHz. So 28 GHz vs 40.8 GHz. That should at least translate to 90s clobber build time savings. So 4-4.5 minutes. Not too shabby. And I'm sure they make good space heaters too. FWIW, my i7-6700K (4+4 cores @ 4.0 GHz) is currently taking ~840s (~14:00) for clobber builds (with Ubuntu 16.04 and a different toolchain however). Those extra cores (even at lower clock speeds) really do matter. _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
