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On Wed, 9 Jan 2002, Brian wrote: > Can this be correct? > > Intuitively, I would expect several CPUs hammering away at the compile to > finish faster than one. Given these numbers, I would have to conclude > that is not just wrong, but absolutely wrong. Compile time increases > linearly with the number of jobs, regardless of the number of CPUs. > > What would cause this? Severe memory bottlenecks? Mike ran make -j 8 which means 8 compiler processes for each "# Makes" in the table. Thus, the first row has 8 parallel processes on a 2-way and the last row has 48 processes on an 8-way. The best ratio is 8 processes on an 8-way which not incidentally also has the lowest time: 57 seconds. -jwb > > -- Brian > > On Tuesday 08 January 2002 10:39 pm, Mike Kravetz wrote: > > -------------------------------------------------------------------- > > mkbench - Time how long it takes to compile the kernel. > > We use 'make -j 8' and increase the number of makes run > > in parallel. Result is average build time in seconds. > > Lower is better. > > -------------------------------------------------------------------- > > # CPUs # Makes Vanilla O(1) haMQ > > -------------------------------------------------------------------- > > 2 1 188 192 184 > > 2 2 366 372 362 > > 2 4 730 742 600 > > 2 6 1096 1112 853 > > 4 1 102 101 95 > > 4 2 196 198 186 > > 4 4 384 386 374 > > 4 6 576 579 487 > > 8 1 58 57 58 > > 8 2 109 108 105 > > 8 4 209 213 186 > > 8 6 309 312 280 > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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