On Fri, Mar 08, 2019 at 02:50:26PM +0100, Martin Liška wrote: > On 3/8/19 1:44 PM, Jan Hubicka wrote: > >> Hi. > >> > >> Thanks to Intel guys, we've done some re-measurement in PR86952 > >> about usage of jump tables when retpolines are used. > >> Numbers prove that disabling of JT should be the best for now. > >> > >> Patch can bootstrap on x86_64-linux-gnu and survives regression tests. > >> > >> Ready to be installed? > > > > OK, thanks! > > I wonder if there is some threshold for extremely large jumptables where > > branchy sequence will loose, but I think it is better to disable them > > than what we have right now. > > I tested switch statements up to 4096 and it was still slower ;)
Try one with 10000000 of entries ;) and also compare code size and data segment size. Jakub