log using resphape,text replace
set processors 1
set obs 1000000
gen i=_n
foreach x of newlist x1-x50 {
  gen `x'=_n
}
preserve
timer on 1
reshape long x, i(i) 
timer off 1
restore

preserve
timer on 2
tolong x,i(i)
timer off 2
restore

preserve
timer on 3
fastreshape long x,i(i)
timer off 3
restore



timer list
di "1=reshape 2=golong 3=fastreshape"