[gambit-list] Is the number of allocated bytes reported by time accurate?

Bradley Lucier lucier at math.purdue.edu
Thu Apr 24 16:25:34 EDT 2014


Ah, yes. A bit confusing, though when writing code to minimize allocations. 

Thanks. 

Brad

> On Apr 24, 2014, at 4:20 PM, Marc Feeley <feeley at iro.umontreal.ca> wrote:
> 
> 
> 
>> On Apr 24, 2014, at 3:58 PM, Bradley Lucier <lucier at math.purdue.edu> wrote:
>> 
>> Marc:
>> 
>> I get
>> 
>>> (time (##bignum.make 2 #f #f))
>> (time (##bignum.make 2 #f #f))
>>    0 ms real time
>>    0 ms cpu time (0 user, 0 system)
>>    no collections
>>    48 bytes allocated
>>    no minor faults
>>    no major faults
>> 4344
>>> (time (cons a b))
>> (time (cons a b))
>>    0 ms real time
>>    0 ms cpu time (0 user, 0 system)
>>    no collections
>>    48 bytes allocated
>>    1 minor fault
>>    no major faults
>> 
>> on a 64-bit machine; I would expect each of them to allocate 24 bytes (two a-digits and a tag in the first one, two slots and a tag in the second).
>> 
>> So, can you explain what's going on?
>> 
>> Brad
> 
> We’ve been over this before… These objects are allocated as movable objects in the heap where 24 bytes are allocated in the fromspace and 24 bytes are allocated in the tospace.  Its just a fair accounting of the space reserved for the object.
> 
> Marc
> 



More information about the Gambit-list mailing list