Re: [PATCH 0/2] KVM: s390: avoid jump tables

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Feb 06, 2018 at 01:30:28PM +0100, David Hildenbrand wrote:
> On 06.02.2018 12:21, Christian Borntraeger wrote:
> > Some old patches refreshed.
> > 
> 
> Certainly the right thing to do. Especially also interesting due to
> retpotline (if we get something like that on s390x). If I remember
> correctly, x86 highly benefits by replacing magic function pointer by
> switch statements.

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.

--
To unsubscribe from this list: send the line "unsubscribe linux-s390" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux