Re: [PATCH 1/2] Memory statistics enhancement.

[Jeff Law <law@redhat.com>]

On 06/03/2015 03:14 AM, Martin Liška wrote:
> On 06/02/2015 07:17 PM, Jeff Law wrote:
>> On 06/02/2015 09:05 AM, Martin Liška wrote:
>>> On 06/02/2015 03:58 PM, Jeff Law wrote:
>>>> On 06/01/2015 10:16 AM, mliska wrote:
>>>>> Hi.
>>>>>
>>>>> Following 2 patches improve memory statistics infrastructure. First one
>>>>> ports pool allocator to the new infrastructure. And the second one makes
>>>>> column alignment properly.
>>>>>
>>>>> Both can bootstrap on x86_64-linux-pc and survive regression tests.
>>>>>
>>>>> Ready for trunk?
>>>>> Thank you,
>>>>> Martin
>>>>>
>>>>> Port pool-allocator memory stats to a new infrastructure.
>>>>>
>>>>> gcc/ChangeLog:
>>>>>
>>>>> 2015-06-02  Martin Liska  <mliska@suse.cz>
>>>>>
>>>>>       * alloc-pool.c (allocate_pool_descriptor): Remove.
>>>>>       (struct pool_output_info): Likewise.
>>>>>       (print_alloc_pool_statistics): Likewise.
>>>>>       (dump_alloc_pool_statistics): Likewise.
>>>>>       * alloc-pool.h (struct pool_usage): New struct.
>>>>>       (pool_allocator::initialize): Change usage of memory statistics
>>>>>       to a new interface.
>>>>>       (pool_allocator::release): Likewise.
>>>>>       (pool_allocator::allocate): Likewise.
>>>>>       (pool_allocator::remove): Likewise.
>>>>>       * mem-stats-traits.h (enum mem_alloc_origin): Add new enum value
>>>>>       for a pool allocator.
>>>>>       * mem-stats.h (struct mem_location): Add new ctor.
>>>>>       (struct mem_usage): Add counter for number of
>>>>>       instances.
>>>>>       (mem_alloc_description::register_descriptor): New overload of
>>>>>       the function.
>>>>    -
>>>>
>>>>> diff --git a/gcc/alloc-pool.h b/gcc/alloc-pool.h
>>>>> index 96a1342..a1727ce 100644
>>>>> --- a/gcc/alloc-pool.h
>>>>> +++ b/gcc/alloc-pool.h
>>>>
>>>>> +  /* Dump usage coupled to LOC location, where TOTAL is sum of all rows.  */
>>>>> +  inline void dump (mem_location *loc, mem_usage &total) const
>>>>> +  {
>>>>> +    char s[4096];
>>>>> +    sprintf (s, "%s:%i (%s)", loc->get_trimmed_filename (),
>>>>> +         loc->m_line, loc->m_function);
>>>> Static sized buffer used in a sprintf where the strings are potentially user controlled.   Not good, even in dumping code, still not good.
>>>>
>>>>> +
>>>>> +    s[48] = '\0';
>>>> ?!?  Presumably you're just truncating the output line here for the subsequent fprintf call.  Consider using a const with a symbolic name rather than the magic "48".  I say "consider" because there's magic constants all over the place in the dumping code. So it may not be worth the effort.  Your call.
>>>>
>>>>    +
>>>>> +  /* Dump header with NAME.  */
>>>>> +  static inline void dump_header (const char *name)
>>>>> +  {
>>>>> +    fprintf (stderr, "%-32s%-48s %6s%11s%16s%17s%12s\n", "Pool name", name,
>>>>> +         "Pools", "Leak", "Peak", "Times", "Elt size");
>>>>> +    print_dash_line ();
>>>>> +  }
>>>>> +
>>>>> +  /* Dump footer.  */
>>>>> +  inline void dump_footer ()
>>>>> +  {
>>>>> +    print_dash_line ();
>>>>> +    fprintf (stderr, "%s%75li%10li\n", "Total", (long)m_instances,
>>>>> +         (long)m_allocated);
>>>>> +    print_dash_line ();
>>>>> +  }
>>>> Note the header is static inline, footer is just inline.  Please try to make them consistent.
>> It doesn't look like you did anything with this.  Is there a reason that the dump_header and dump_footer have different linkage?  Also the linkage/return type for dump_header should be on its own line.
>>
>> With that fixed, this is OK for the trunk.
>>
>> jeff
>
> Hi Jeff.
>
> Different linkage is because of dump_header is just a generic header unrelated to any real numbers.
> On the other hand, dump_footer is called on a total instance.
Right, but why does that affect linkage?   Sorry to keep harping on this 
minor issue, but something just doesn't make any sense to me.

>
> I've just identified that the whole memory statistics infrastructure lacks correct GNU formatting
> in case of C++ member functions. I'm going to fix it in a different patch.
Excellent.  Thanks,

jeff