On Tue, Sep 4, 2012 at 3:19 AM, Gregory Szorc <g...@mozilla.com> wrote: > I re-ran some builds on my desktop with my instrumented build system that > records system metrics and an SSD clobber build was only ~50s faster than > the same build on a 7200RPM drive. This comes out to ~5%, which isn't much. > Both results were on a freshly booted virtual machine (read: empty page > cache) that had access to 12GB of memory. This was also with ccache disabled > (all my previous measurements on list posts and my personal blog were with > ccache enabled, which definitely has an impact on I/O).
Having no page cache and no ccache is great for getting stable numbers, but not very realistic. In practice, most compiles will have the page cache populated, so it probably won't even be 5%. (On the other hand, in principle ccache should increase the amount of on-disk data being accessed, and therefore *increase* the value of an SSD. But I haven't noticed this in practice.) _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
