On December 30, 2018 11:21:07 PM PST, Nadav Amit wrote:
>It is sometimes beneficial to have a restartable sequence - very few
>instructions which if they are preempted jump to a predefined point.
>
>To provide such functionality on x86-64, we use an empty REX-prefix
>(opcode 0x40) as an
> On Jan 3, 2019, at 3:40 PM, Andi Kleen wrote:
>
>> Thanks for the explanations. I don’t think it would work (e.g., IRQs). I can
>> avoid generalizing and just detect the "magic sequence” of the code, but let
>> me give it some more thought.
>
> If you ask me I would just use compiler profile
> Thanks for the explanations. I don’t think it would work (e.g., IRQs). I can
> avoid generalizing and just detect the "magic sequence” of the code, but let
> me give it some more thought.
If you ask me I would just use compiler profile feedback or autofdo (if your
compiler has a working
> On Jan 3, 2019, at 2:48 PM, Andi Kleen wrote:
>
>> Ok… I’ll try to think about another solution. Just note that this is just
>> used as a hint to avoid unnecessary lookups. (IOW, nothing will break if the
>> prefix is used.)
>
> Are you sure actually?
>
> The empty prefix could mean 8bit
> Ok… I’ll try to think about another solution. Just note that this is just
> used as a hint to avoid unnecessary lookups. (IOW, nothing will break if the
> prefix is used.)
Are you sure actually?
The empty prefix could mean 8bit register accesses.
> > You're doing the equivalent of patching a
> On Jan 3, 2019, at 2:21 PM, Andi Kleen wrote:
>
> Nadav Amit writes:
>
> I see another poor man's attempt to reinvent TSX.
>
>> It is sometimes beneficial to have a restartable sequence - very few
>> instructions which if they are preempted jump to a predefined point.
>>
>> To provide such
Nadav Amit writes:
I see another poor man's attempt to reinvent TSX.
> It is sometimes beneficial to have a restartable sequence - very few
> instructions which if they are preempted jump to a predefined point.
>
> To provide such functionality on x86-64, we use an empty REX-prefix
> (opcode
> On Dec 31, 2018, at 12:08 PM, Andy Lutomirski wrote:
>
> On Sun, Dec 30, 2018 at 11:20 PM Nadav Amit wrote:
>> It is sometimes beneficial to have a restartable sequence - very few
>> instructions which if they are preempted jump to a predefined point.
>>
>> To provide such functionality on
On Sun, Dec 30, 2018 at 11:20 PM Nadav Amit wrote:
>
> It is sometimes beneficial to have a restartable sequence - very few
> instructions which if they are preempted jump to a predefined point.
>
> To provide such functionality on x86-64, we use an empty REX-prefix
> (opcode 0x40) as an
It is sometimes beneficial to have a restartable sequence - very few
instructions which if they are preempted jump to a predefined point.
To provide such functionality on x86-64, we use an empty REX-prefix
(opcode 0x40) as an indication for instruction in such a sequence. Before
calling the
10 matches
Mail list logo
