On Thu, 8 Feb 2018 11:09:15 +0100 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > On 02/08/2018 09:58 AM, Heiko Carstens wrote: > > > If you look at the generated code for the first patch: gcc now generates > > its own jump table which then jumps (indirectly) to a brasl... So it's two > > instead of one branch. > > I'm not saying that this patch is not good, but there seem be a wrong > > assumptions about the benefit here. > > I will now use the following patch description. > > > > KVM: s390: use switch vs jump table in intercept.c > > Instead of having huge jump tables for function selection, > let's use normal switch/case statements for the instruction > handlers in intercept.c We can now also get rid of > intercept_handler_t. > > This allows the compiler to make the right decision depending > on the situation (e.g. avoid jump-tables for thunks). > > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx> > Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> > Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> > > commit cf392b582009f8ee4ef859f935dd9f67f855ccaf > Author: Christian Borntraeger <borntraeger@xxxxxxxxxx> > AuthorDate: Fri Apr 8 17:52:39 2016 +0200 > Commit: Christian Borntraeger <borntraeger@xxxxxxxxxx> > CommitDate: Thu Feb 8 10:07:42 2018 +0000 > > KVM: s390: use switch vs jump table in priv.c > > Instead of having huge jump tables for function selection, > let's use normal switch/case statements for the instruction > handlers in priv.c > > This allows the compiler to make the right decision depending > on the situation (e.g. avoid jump-tables for thunks). > > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> > Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx> > Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> > Fine with me.
