Re: Slow memory access, Not understood when using integer@(mem address)

[Jussi Lahtinen <jussi.lahtinen@xxxxxxxxx>]

Note that assigning address to structure is not checked at all.
Thus example "Dim bomb As Myint = CPointer(0)" is accepted by Gambas. The
crash happens only when accessing the address (example "Inc bomb").
So, perhaps Integer@() could cache its checks for it to be faster... but
this could be a lot of trouble for little benefit. Or it could be unsafe as
default like many memory access functions.


Jussi


On Thu, Sep 24, 2026 at 10:10 PM Jussi Lahtinen <jussi.lahtinen@xxxxxxxxx>
wrote:

> This:  Integer@(mptr) = Integer@(mptr) + 1
> does a lot more than this: vptr.counter = vptr.counter + 1
>
> They are not quite equal.
> First one fetches Gambas integer from the memory address twice and then
> adds one. The other one does everything completely within Gambas. IE adds
> one to the variable in Gambas.
>
>
> Jussi
>
>
>
> On Thu, Sep 24, 2026 at 12:03 AM Brian G <brian@xxxxxxxxxxxxxxxx> wrote:
>
>> On 9/23/26 13:36, Brian G wrote:
>> > I have attached a small project that tests the access speed to memory
>> > using integer@(memory address), as used for Linux library interfaces.
>> > I am sorry but 44 times slower than access through a struct pointer is
>> > just a bit much to accept!
>> > Using this structure and allocating a data space
>> > Public Struct myint
>> >     counter As Integer
>> > End Struct
>> > mptr=alloc(100)
>> > Here is an example using integer@(xx) compared to accessing thru a
>> > structure 1 million times
>> >
>> > Test Speed to Access script Variables using integer@ptr access method,
>> > no locking
>> > using: Integer@(mptr) = Integer@(mptr) + 1
>> > Total time 4.40942561195698
>> >
>> > Test Speed to Access script Variables using struct direct access
>> > method, no locking
>> > dim vptr as myint = mptr
>> > using: Inc vptr.counter and tested with vptr.counter = vptr.counter +
>> > 1, same results
>> > Total time 0.098687710007653
>> >
>> > Struct access is 44.6810829482192 times faster than integer @ access
>> > to the same memory address
>> >
>> > Can this be fixed, it is pretty bad!
>> >
>> Update
>>
>> using fast unsafe the values are interesting so normal is about 1442
>> times slower than fast unsafe version
>>
>> Hello world
>> Test Speed to Access script Variables using integer@ptr access method,
>> no locking
>> Total time 0.003050090977922
>> Test Speed to Access script Variables using struct direct access method,
>> no locking
>> Total time 0.041397490072995
>> Struct access is now 13.5725427118894 times slower..... confusing such a
>> big difference
>>
>> --
>> ~~~~ Brian
>>
>>