servo-mac1 and servo-mac8 take over 20 minutes to build servo

[jdm]

This is unreasonably long. The other mac builders take 18 minutes; servo-mac7 takes 28.

[SimonSapin]

Our mac machines have varying hardware, but that doesn’t seem to explain this particular discrepancy.

$ for i in $(seq 9); (echo -ne "servo-mac$i  "; ssh servo-mac$i.servo.org 'echo "$(sysctl -n hw.physicalcpu) / $(sysctl -n hw.logicalcpu)  $(sysctl -n machdep.cpu.brand_string)"') 
servo-mac1  4 / 8  Intel(R) Core(TM) i7-2635QM CPU @ 2.00GHz
servo-mac2  4 / 8  Intel(R) Core(TM) i7-3720QM CPU @ 2.60GHz
servo-mac3  4 / 8  Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz
servo-mac4  4 / 8  Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz
servo-mac5  4 / 8  Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz
servo-mac6  4 / 8  Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz
servo-mac7  2 / 4  Intel(R) Core(TM) i5-4278U CPU @ 2.60GHz
servo-mac8  4 / 8  Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz
servo-mac9  2 / 4  Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz

[jdm]

servo-mac9 takes ~40 minutes to build.

[jdm]

The figures might have changed for other machines; a number of them have been replaced with new ones since I filed this issue.