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New Computer
I recently upgraded to a new laptop, a Dell Latitude D830 (Santa Rosa chipset) running a 2.4GHz Core 2 Duo with 4GB of RAM and a new DX10 video card, the nVidia Quadro NVS 140M. I went ahead and installed Vista 64-bit on the machine, in order to be able to take full advantage of the 4GB of RAM. Since I do most of my MAME development on this machine, compliation speeds for building MAME are of utmost importance.
Below is a summary of complete build times for MAME using both my previous laptop (Dell Inspiron 8600 running a 2.0GHz Pentium-M with 2GB RAM) and the new one. I tested both debug and optimized builds using both Visual Studio 2005 and gcc.
| Old System | New System | Improvement | |
|---|---|---|---|
| CPU Cores | 1 | 2 | +100% |
| RAM | 2GB | 4GB | +100% |
| Build with VS2005, DEBUG=1 SYMBOLS=1 | 9:38 | 4:15 | -56% |
| Build with VS2005, PM=1 | 11:27 | 4:42 | -59% |
| Build with VS2005, PM=1 MAXOPT=1 | 20:48 | 10:51 | -48% |
| Build with gcc, DEBUG=1 SYMBOLS=1 | 10:20 | 5:02 | -51% |
| Build with gcc, PM=1 | 17:05 | 6:49 | -60% |
Since the new machine is a dual-core system, I was curious to find out if running a make with -j3 was better than running with -j2. I had heard that it is best to run make with a -j parameter equal to the number of CPUs you have available, plus 1 to help take advantage of extra CPU power while waiting for I/O to complete on other threads. Using the Visual Studio 2005 SP1 build as a test case, it turns out that -j3 does win slightly over -j2, producing a complete MAME build in 4:15 (-j3) versus 4:25 (-j2). Interestingly, when I tried this on my old single-core machine, it was slightly slower to use -j2 versus -j1.
I was also curious to see how much slower it was to do an optimized build using the Visual Studio compilers. A basic optimized build is not that much slower than an unoptimized build (4:42 versus 4:15). However, turning on link-time code generation -- which reduces the final output EXE size by a large amount and provides a marginal additional speedup -- more than doubles the build time to 10:51.
Comparing Visual Studio builds to gcc builds, it seems that the difference is not as pronounced as the last time I measured it (5:02 versus 4:15 for the debug build). This is partly due to the extra overhead of Visual Studio 2005, which is noticeably slower than Visual Studio .NET 2003, which I haven't tried installing under Vista. In the end, it doesn't much matter since debugging with Visual Studio is a huge win over trying to debug with gdb, so I'd still use it a lot even if it were slower!