Re: Malloc tests
On Fri, Jan 7, 2022 at 8:25 PM zack leung wrote:
>
> I think that the malloc tests is calculated differently than alloc_size+
> allocsize mod it looks like this
> *alloc_size = (uintptr_t) next_block + HEAP_ALLOC_BONUS - alloc_begin;
> when i run the comparison i get 8 (with heap alignment) and the function
> gives me 12.
> is the heap alloc bonus part of the current block?
The allocation extra is intended to ensure the block is in even
"pages". The size
of a page is specified when the heap instance is created but it is
CPU_HEAP_ALIGMENT for this specific heap.
If CPU_HEAP_ALIGMENT is 16 and you malloc(13), then the block
returned to you is really 16 bytes in size and you should only expect 13 to
be there.
The "bonus" will be between 0 and CPU_HEAP_ALIGNMENT - 1.
But the allocated size adjusted up to the next even multiple of
CPU_HEAP_ALIGNMENT should be the usable size.
--joel
>
> On Thu, 6 Jan 2022 at 21:28, Joel Sherrill wrote:
>>
>> On Thu, Jan 6, 2022 at 2:55 PM Gedare Bloom wrote:
>> >
>> > On Tue, Jan 4, 2022 at 6:10 PM zack leung wrote:
>> > >
>> > > Helllo ,
>> > > I'm working on a patch for malloc_get_usable size right now so far i have
>> > > this test case for malloc, I just make sure that the value is null and i
>> > > just malloc an int and then i make a call to the function malloc_usable
>> > > size and then i compare it like this.
>> > >
>> > > static void test_malloc_usablesize( void ){
>> > >int * a = malloc(sizeof(int));
>> > >rtems_test_assert((int) malloc_usable_size(a) == 12);
>> > >free (a);
>> > >
>> > >int * b = NULL;
>> > >rtems_test_assert( 0 == malloc_usable_size(b));
>> > >free(b);
>> > >
>> > >
>> > > }
>> > > Is there a good amount of storage to allocate? Also I heard someone made
>> > > a
>> >
>> > I think that this test case is quite brittle. The "usable size" will
>> > depend on the implementation details of malloc, and the conditions of
>> > the heap when the allocation request gets made. I don't have better
>> > ideas however for how to test the correctness of the usable_size
>> > function. Maybe there are certain sequences of malloc/free calls that
>> > can be relied upon to give you deterministic sizes of allocations?
>>
>> My suggestion in private chat was that you can depend on the
>> malloc heap being initialized with CPU_HEAP_ALIGNMENT. That's
>> what that macro is specifically for. It is used in
>> include/rtems/score/wkspaceinit*.h
>> and has been since the dawn of time.
>>
>> Then the size for a valid pointer from malloc() should be between
>> the allocated size and the next number on a CPU_HEAP_ALIGNMENT
>> boundary. I think the exact number is actually something like this:
>>
>> expected = alloc_size;
>> mod = alloc_size % CPU_HEAP_ALIGMENT;
>> expected += mod;
>>
>> Adding a helper function in the test to compute the expected
>> size allocated and validate the return may be wise if multiple
>> size allocations are going to be tested.
>>
>>
>> > > formatter for rtems source files. Can someone tell me how to use it and
>> > > if
>> > > it is on the main branch?
>> >
>> > This was part of a gsoc project last year. We haven't quite made the
>> > switch over to it and the associated coding style I think, but you can
>> > find the code via
>> > https://devel.rtems.org/wiki/GSoC/2021#StudentsSummerofCodeTrackingTable
>> > the student was Meh Mbeh Ida Delphine
>> >
>> >
>> > > ___
>> > > devel mailing list
>> > > devel@rtems.org
>> > > http://lists.rtems.org/mailman/listinfo/devel
>> > ___
>> > devel mailing list
>> > devel@rtems.org
>> > http://lists.rtems.org/mailman/listinfo/devel
___
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devel@rtems.org
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Re: Malloc tests
There a way to get the same values used to make the calculation in malloc
get usable size?
Bump
Il ven 7 gen 2022, 21:25 zack leung ha scritto:
> I think that the malloc tests is calculated differently than alloc_size+
> allocsize mod it looks like this
> *alloc_size = (uintptr_t) next_block + HEAP_ALLOC_BONUS - alloc_begin;
> when i run the comparison i get 8 (with heap alignment) and the function
> gives me 12.
> is the heap alloc bonus part of the current block?
>
> On Thu, 6 Jan 2022 at 21:28, Joel Sherrill wrote:
>
>> On Thu, Jan 6, 2022 at 2:55 PM Gedare Bloom wrote:
>> >
>> > On Tue, Jan 4, 2022 at 6:10 PM zack leung
>> wrote:
>> > >
>> > > Helllo ,
>> > > I'm working on a patch for malloc_get_usable size right now so far i
>> have
>> > > this test case for malloc, I just make sure that the value is null
>> and i
>> > > just malloc an int and then i make a call to the function
>> malloc_usable
>> > > size and then i compare it like this.
>> > >
>> > > static void test_malloc_usablesize( void ){
>> > >int * a = malloc(sizeof(int));
>> > >rtems_test_assert((int) malloc_usable_size(a) == 12);
>> > >free (a);
>> > >
>> > >int * b = NULL;
>> > >rtems_test_assert( 0 == malloc_usable_size(b));
>> > >free(b);
>> > >
>> > >
>> > > }
>> > > Is there a good amount of storage to allocate? Also I heard someone
>> made a
>> >
>> > I think that this test case is quite brittle. The "usable size" will
>> > depend on the implementation details of malloc, and the conditions of
>> > the heap when the allocation request gets made. I don't have better
>> > ideas however for how to test the correctness of the usable_size
>> > function. Maybe there are certain sequences of malloc/free calls that
>> > can be relied upon to give you deterministic sizes of allocations?
>>
>> My suggestion in private chat was that you can depend on the
>> malloc heap being initialized with CPU_HEAP_ALIGNMENT. That's
>> what that macro is specifically for. It is used in
>> include/rtems/score/wkspaceinit*.h
>> and has been since the dawn of time.
>>
>> Then the size for a valid pointer from malloc() should be between
>> the allocated size and the next number on a CPU_HEAP_ALIGNMENT
>> boundary. I think the exact number is actually something like this:
>>
>> expected = alloc_size;
>> mod = alloc_size % CPU_HEAP_ALIGMENT;
>> expected += mod;
>>
>> Adding a helper function in the test to compute the expected
>> size allocated and validate the return may be wise if multiple
>> size allocations are going to be tested.
>>
>>
>> > > formatter for rtems source files. Can someone tell me how to use it
>> and if
>> > > it is on the main branch?
>> >
>> > This was part of a gsoc project last year. We haven't quite made the
>> > switch over to it and the associated coding style I think, but you can
>> > find the code via
>> >
>> https://devel.rtems.org/wiki/GSoC/2021#StudentsSummerofCodeTrackingTable
>> > the student was Meh Mbeh Ida Delphine
>> >
>> >
>> > > ___
>> > > devel mailing list
>> > > devel@rtems.org
>> > > http://lists.rtems.org/mailman/listinfo/devel
>> > ___
>> > devel mailing list
>> > devel@rtems.org
>> > http://lists.rtems.org/mailman/listinfo/devel
>>
>
___
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
Re: Malloc tests
I think that the malloc tests is calculated differently than alloc_size+
allocsize mod it looks like this
*alloc_size = (uintptr_t) next_block + HEAP_ALLOC_BONUS - alloc_begin;
when i run the comparison i get 8 (with heap alignment) and the function
gives me 12.
is the heap alloc bonus part of the current block?
On Thu, 6 Jan 2022 at 21:28, Joel Sherrill wrote:
> On Thu, Jan 6, 2022 at 2:55 PM Gedare Bloom wrote:
> >
> > On Tue, Jan 4, 2022 at 6:10 PM zack leung
> wrote:
> > >
> > > Helllo ,
> > > I'm working on a patch for malloc_get_usable size right now so far i
> have
> > > this test case for malloc, I just make sure that the value is null and
> i
> > > just malloc an int and then i make a call to the function
> malloc_usable
> > > size and then i compare it like this.
> > >
> > > static void test_malloc_usablesize( void ){
> > >int * a = malloc(sizeof(int));
> > >rtems_test_assert((int) malloc_usable_size(a) == 12);
> > >free (a);
> > >
> > >int * b = NULL;
> > >rtems_test_assert( 0 == malloc_usable_size(b));
> > >free(b);
> > >
> > >
> > > }
> > > Is there a good amount of storage to allocate? Also I heard someone
> made a
> >
> > I think that this test case is quite brittle. The "usable size" will
> > depend on the implementation details of malloc, and the conditions of
> > the heap when the allocation request gets made. I don't have better
> > ideas however for how to test the correctness of the usable_size
> > function. Maybe there are certain sequences of malloc/free calls that
> > can be relied upon to give you deterministic sizes of allocations?
>
> My suggestion in private chat was that you can depend on the
> malloc heap being initialized with CPU_HEAP_ALIGNMENT. That's
> what that macro is specifically for. It is used in
> include/rtems/score/wkspaceinit*.h
> and has been since the dawn of time.
>
> Then the size for a valid pointer from malloc() should be between
> the allocated size and the next number on a CPU_HEAP_ALIGNMENT
> boundary. I think the exact number is actually something like this:
>
> expected = alloc_size;
> mod = alloc_size % CPU_HEAP_ALIGMENT;
> expected += mod;
>
> Adding a helper function in the test to compute the expected
> size allocated and validate the return may be wise if multiple
> size allocations are going to be tested.
>
>
> > > formatter for rtems source files. Can someone tell me how to use it
> and if
> > > it is on the main branch?
> >
> > This was part of a gsoc project last year. We haven't quite made the
> > switch over to it and the associated coding style I think, but you can
> > find the code via
> > https://devel.rtems.org/wiki/GSoC/2021#StudentsSummerofCodeTrackingTable
> > the student was Meh Mbeh Ida Delphine
> >
> >
> > > ___
> > > devel mailing list
> > > devel@rtems.org
> > > http://lists.rtems.org/mailman/listinfo/devel
> > ___
> > devel mailing list
> > devel@rtems.org
> > http://lists.rtems.org/mailman/listinfo/devel
>
___
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
Re: Malloc tests
On Thu, Jan 6, 2022 at 2:55 PM Gedare Bloom wrote:
>
> On Tue, Jan 4, 2022 at 6:10 PM zack leung wrote:
> >
> > Helllo ,
> > I'm working on a patch for malloc_get_usable size right now so far i have
> > this test case for malloc, I just make sure that the value is null and i
> > just malloc an int and then i make a call to the function malloc_usable
> > size and then i compare it like this.
> >
> > static void test_malloc_usablesize( void ){
> >int * a = malloc(sizeof(int));
> >rtems_test_assert((int) malloc_usable_size(a) == 12);
> >free (a);
> >
> >int * b = NULL;
> >rtems_test_assert( 0 == malloc_usable_size(b));
> >free(b);
> >
> >
> > }
> > Is there a good amount of storage to allocate? Also I heard someone made a
>
> I think that this test case is quite brittle. The "usable size" will
> depend on the implementation details of malloc, and the conditions of
> the heap when the allocation request gets made. I don't have better
> ideas however for how to test the correctness of the usable_size
> function. Maybe there are certain sequences of malloc/free calls that
> can be relied upon to give you deterministic sizes of allocations?
My suggestion in private chat was that you can depend on the
malloc heap being initialized with CPU_HEAP_ALIGNMENT. That's
what that macro is specifically for. It is used in
include/rtems/score/wkspaceinit*.h
and has been since the dawn of time.
Then the size for a valid pointer from malloc() should be between
the allocated size and the next number on a CPU_HEAP_ALIGNMENT
boundary. I think the exact number is actually something like this:
expected = alloc_size;
mod = alloc_size % CPU_HEAP_ALIGMENT;
expected += mod;
Adding a helper function in the test to compute the expected
size allocated and validate the return may be wise if multiple
size allocations are going to be tested.
> > formatter for rtems source files. Can someone tell me how to use it and if
> > it is on the main branch?
>
> This was part of a gsoc project last year. We haven't quite made the
> switch over to it and the associated coding style I think, but you can
> find the code via
> https://devel.rtems.org/wiki/GSoC/2021#StudentsSummerofCodeTrackingTable
> the student was Meh Mbeh Ida Delphine
>
>
> > ___
> > devel mailing list
> > devel@rtems.org
> > http://lists.rtems.org/mailman/listinfo/devel
> ___
> devel mailing list
> devel@rtems.org
> http://lists.rtems.org/mailman/listinfo/devel
___
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
Re: Malloc tests
On Tue, Jan 4, 2022 at 6:10 PM zack leung wrote:
>
> Helllo ,
> I'm working on a patch for malloc_get_usable size right now so far i have
> this test case for malloc, I just make sure that the value is null and i
> just malloc an int and then i make a call to the function malloc_usable
> size and then i compare it like this.
>
> static void test_malloc_usablesize( void ){
>int * a = malloc(sizeof(int));
>rtems_test_assert((int) malloc_usable_size(a) == 12);
>free (a);
>
>int * b = NULL;
>rtems_test_assert( 0 == malloc_usable_size(b));
>free(b);
>
>
> }
> Is there a good amount of storage to allocate? Also I heard someone made a
I think that this test case is quite brittle. The "usable size" will
depend on the implementation details of malloc, and the conditions of
the heap when the allocation request gets made. I don't have better
ideas however for how to test the correctness of the usable_size
function. Maybe there are certain sequences of malloc/free calls that
can be relied upon to give you deterministic sizes of allocations?
> formatter for rtems source files. Can someone tell me how to use it and if
> it is on the main branch?
This was part of a gsoc project last year. We haven't quite made the
switch over to it and the associated coding style I think, but you can
find the code via
https://devel.rtems.org/wiki/GSoC/2021#StudentsSummerofCodeTrackingTable
the student was Meh Mbeh Ida Delphine
> ___
> devel mailing list
> devel@rtems.org
> http://lists.rtems.org/mailman/listinfo/devel
___
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
Malloc tests
Helllo ,
I'm working on a patch for malloc_get_usable size right now so far i have
this test case for malloc, I just make sure that the value is null and i
just malloc an int and then i make a call to the function malloc_usable
size and then i compare it like this.
static void test_malloc_usablesize( void ){
int * a = malloc(sizeof(int));
rtems_test_assert((int) malloc_usable_size(a) == 12);
free (a);
int * b = NULL;
rtems_test_assert( 0 == malloc_usable_size(b));
free(b);
}
Is there a good amount of storage to allocate? Also I heard someone made a
formatter for rtems source files. Can someone tell me how to use it and if
it is on the main branch?
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