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>
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