Put biggest buffer 1st in CTS_CLK_BUFFER_LIST

[maliberty]

In sky130/openlane/sky130_fd_sc_hd/config.tcl you have:

set ::env(CTS_CLK_BUFFER_LIST) "sky130_fd_sc_hd__clkbuf_2 sky130_fd_sc_hd__clkbuf_4 sky130_fd_sc_hd__clkbuf_8"

it is currently better to put the largest buffer first like:

set ::env(CTS_CLK_BUFFER_LIST) "sky130_fd_sc_hd__clkbuf_8 sky130_fd_sc_hd__clkbuf_4 sky130_fd_sc_hd__clkbuf_2"

OR will eventually not care but for now this gives better results.

@antonblanchard FYI

[maliberty]

This applies to hs and the other config.tcl too

[RTimothyEdwards]

Thanks, done.