On Wed, Apr 29, 2020 at 11:06:58PM -0500, Josh Poimboeuf wrote: > On Thu, Apr 30, 2020 at 10:32:17AM +0800, changhuaixin wrote: > > > > > > > On Apr 29, 2020, at 4:49 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > > > > On Wed, Apr 29, 2020 at 02:46:24PM +0800, Huaixin Chang wrote: > > >> Move building of fast lookup table from boot to sorttable tool. This saves us > > >> 6380us boot time on Intel(R) Xeon(R) CPU E5-2682 v4 @ 2.50GHz with cores. > > > > > > And what does it add to the build time? > > > > It takes a little more than 7ms to build fast lookup table in > > sorttable on the same CPU. And it is on the critical path. > > Thanks, I like it. It will help make the in-kernel unwinder even > simpler. And it will enable unwinding from early boot. > > Maybe someday we can move all the table sorting code into objtool, once > we have objtool running on vmlinux.o. > > I'll try to review the patches soon. BTW, another cool feature would be for sorttable to run on modules during the module linking phase. -- Josh
