Cycle time has regressed by 30 mins

[alexcrichton]

The android builders (the slowest ones) have slowed down by an extra half hour.

The test step is taking a half hour longer because it's rebuilding everything which was previously built. Looking at the history it looks like #17095 introduced the regression, so it looks like something is going wrong with rebuilding jemalloc (starting the whole build process over again).

cc @thestinger

[alexcrichton]

Looking at the relevant target, perhaps jemalloc is touching files in the source directory?

[brson]

Any progress on this?

[alexcrichton]

It appears that jemalloc is touching a file called VERSION at the root of the source tree as part of the configure step.

This is causing the target to be rebuilt on android because the VERSION file is touched twice, once for the host arch and one for android. Touching it a second time when building android invalidates the previously built host artifacts, triggering the entire recompilation.

[alexcrichton]

relevant commit: jemalloc/jemalloc@a5a658a