[Lldb-commits] [lldb] r105834 - in /lldb/trunk: include/lldb/Symbol/Symtab.h source/Symbol/Symtab.cpp
Greg Clayton
gclayton at apple.com
Wed Jun 16 09:27:57 PDT 2010
We start with "Sketch" from the /Developer/Expamples. It loads 91 shared libraries right off the bat, and if you then type:
(lldb) log timers enable
(lldb) breakpoint set --name main
(lldb) log timers disable
All of the symbol tables will be pulled in, and it will dump the timing information.
You will first need to add a scoped timer to the top of:
Symtab::SortSymbolIndexesByValue()
The easiest way is:
Timer scoped_timer (__PRETTY_FUNCTION__,__PRETTY_FUNCTION__);
Then you should see an entry in the timer dump for Symtab::SortSymbolIndexesByValue when the "log timers disable" is run with a total time.
On Jun 16, 2010, at 9:21 AM, Owen Anderson wrote:
> Do you have a test I can use to measure this?
>
> --Owen
>
> On Jun 16, 2010, at 9:18 AM, Greg Clayton wrote:
>
>> We will need to use the scoped timers to make sure that performance doesn't degrade on MacOSX. File size, I don't much care about, but I do care about performance. And the last time I checked the performance, there was a 3x performance difference (qsort being 3x faster than std::sort (with gcc 4.2)). Symbols tables are high up on the list when it comes to things we need to keep fast.
>>
>> Greg Clayton
>>
>>
>> On Jun 15, 2010, at 3:25 PM, Owen Anderson wrote:
>>
>>> Ping?
>>>
>>> On Jun 11, 2010, at 2:40 PM, Owen Anderson wrote:
>>>
>>>> OK, so I did some measurement on this issue, using optimized (-Os) builds of LLDB, without debug symbols, targeting x86-64.
>>>>
>>>> When using qsort_r, Symtab.o is 43KB.
>>>> When using std::sort, Symtab.o is 46KB.
>>>> A 7% increase in file size on a single file.
>>>>
>>>> The qsort_r version of LLDB.framework is 32,840,512 bytes.
>>>> The std::sort version of LLDB.framework is 32,840,937 bytes.
>>>> A 0.001% increase in file size of the overall library. :-)
>>>>
>>>> Interestingly, it appears that those extra symbols get coalesced with ones already present (presumably in the LLVM libraries), so it doesn't actually add much at all to the resulting library.
>>>>
>>>> --Owen
>>>>
>>>> On Jun 11, 2010, at 2:03 PM, Jason Molenda wrote:
>>>>
>>>>> Please back this change out Owen, until you've addressed the point Greg made here -
>>>>> http://lists.cs.uiuc.edu/pipermail/lldb-dev/2010-June/000039.html
>>>>>
>>>>> J
>>>>>
>>>>> On Jun 11, 2010, at 1:52 PM, Owen Anderson wrote:
>>>>>
>>>>>> Author: resistor
>>>>>> Date: Fri Jun 11 15:52:57 2010
>>>>>> New Revision: 105834
>>>>>>
>>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=105834&view=rev
>>>>>> Log:
>>>>>> Replace qsort_r with std::sort. This gets rid of a lot of portability
>>>>>> ickiness, and is cleaner to boot.
>>>>>>
>>>>>> I'm fairly confident that I converted the comparator over properly,
>>>>>> and what testing I could figure out how to run seemed to pass, but it
>>>>>> would be great if someone in the know could check behind me.
>>>>>>
>>>>>> Modified:
>>>>>> lldb/trunk/include/lldb/Symbol/Symtab.h
>>>>>> lldb/trunk/source/Symbol/Symtab.cpp
>>>>>>
>>>>>> Modified: lldb/trunk/include/lldb/Symbol/Symtab.h
>>>>>> URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Symbol/Symtab.h?rev=105834&r1=105833&r2=105834&view=diff
>>>>>> ==============================================================================
>>>>>> --- lldb/trunk/include/lldb/Symbol/Symtab.h (original)
>>>>>> +++ lldb/trunk/include/lldb/Symbol/Symtab.h Fri Jun 11 15:52:57 2010
>>>>>> @@ -59,8 +59,6 @@
>>>>>> typedef collection::iterator iterator;
>>>>>> typedef collection::const_iterator const_iterator;
>>>>>>
>>>>>> - static int CompareSymbolValueByIndex (void *thunk, const void *a, const void *b);
>>>>>> - static int CompareSymbolValueByIndexLinux (const void *a, const void *b, void *thunk);
>>>>>> void InitNameIndexes ();
>>>>>> void InitAddressIndexes ();
>>>>>>
>>>>>>
>>>>>> Modified: lldb/trunk/source/Symbol/Symtab.cpp
>>>>>> URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Symbol/Symtab.cpp?rev=105834&r1=105833&r2=105834&view=diff
>>>>>> ==============================================================================
>>>>>> --- lldb/trunk/source/Symbol/Symtab.cpp (original)
>>>>>> +++ lldb/trunk/source/Symbol/Symtab.cpp Fri Jun 11 15:52:57 2010
>>>>>> @@ -214,46 +214,36 @@
>>>>>> const Symbol *symbols;
>>>>>> };
>>>>>>
>>>>>> -int
>>>>>> -Symtab::CompareSymbolValueByIndex (void *thunk, const void *a, const void *b)
>>>>>> -{
>>>>>> - const Symbol *symbols = (const Symbol *)thunk;
>>>>>> - uint32_t index_a = *((uint32_t *) a);
>>>>>> - uint32_t index_b = *((uint32_t *) b);
>>>>>> -
>>>>>> - addr_t value_a;
>>>>>> - addr_t value_b;
>>>>>> - if (symbols[index_a].GetValue().GetSection() == symbols[index_b].GetValue().GetSection())
>>>>>> - {
>>>>>> - value_a = symbols[index_a].GetValue ().GetOffset();
>>>>>> - value_b = symbols[index_b].GetValue ().GetOffset();
>>>>>> - }
>>>>>> - else
>>>>>> - {
>>>>>> - value_a = symbols[index_a].GetValue ().GetFileAddress();
>>>>>> - value_b = symbols[index_b].GetValue ().GetFileAddress();
>>>>>> - }
>>>>>> -
>>>>>> - if (value_a == value_b)
>>>>>> - {
>>>>>> - // The if the values are equal, use the original symbol user ID
>>>>>> - lldb::user_id_t uid_a = symbols[index_a].GetID();
>>>>>> - lldb::user_id_t uid_b = symbols[index_b].GetID();
>>>>>> - if (uid_a < uid_b)
>>>>>> - return -1;
>>>>>> - if (uid_a > uid_b)
>>>>>> - return 1;
>>>>>> - return 0;
>>>>>> - }
>>>>>> - else if (value_a < value_b)
>>>>>> - return -1;
>>>>>> -
>>>>>> - return 1;
>>>>>> -}
>>>>>> +namespace {
>>>>>> + struct SymbolIndexComparator {
>>>>>> + const std::vector<Symbol>& symbols;
>>>>>> + SymbolIndexComparator(const std::vector<Symbol>& s) : symbols(s) { }
>>>>>> + bool operator()(uint32_t index_a, uint32_t index_b) {
>>>>>> + addr_t value_a;
>>>>>> + addr_t value_b;
>>>>>> + if (symbols[index_a].GetValue().GetSection() == symbols[index_b].GetValue().GetSection()) {
>>>>>> + value_a = symbols[index_a].GetValue ().GetOffset();
>>>>>> + value_b = symbols[index_b].GetValue ().GetOffset();
>>>>>> + } else {
>>>>>> + value_a = symbols[index_a].GetValue ().GetFileAddress();
>>>>>> + value_b = symbols[index_b].GetValue ().GetFileAddress();
>>>>>> + }
>>>>>>
>>>>>> -int Symtab::CompareSymbolValueByIndexLinux(const void* a, const void* b, void* thunk)
>>>>>> -{
>>>>>> - return CompareSymbolValueByIndex(thunk, a, b);
>>>>>> + if (value_a == value_b) {
>>>>>> + // The if the values are equal, use the original symbol user ID
>>>>>> + lldb::user_id_t uid_a = symbols[index_a].GetID();
>>>>>> + lldb::user_id_t uid_b = symbols[index_b].GetID();
>>>>>> + if (uid_a < uid_b)
>>>>>> + return true;
>>>>>> + if (uid_a > uid_b)
>>>>>> + return false;
>>>>>> + return false;
>>>>>> + } else if (value_a < value_b)
>>>>>> + return true;
>>>>>> +
>>>>>> + return false;
>>>>>> + }
>>>>>> + };
>>>>>> }
>>>>>>
>>>>>> void
>>>>>> @@ -263,13 +253,8 @@
>>>>>> if (indexes.size() <= 1)
>>>>>> return;
>>>>>>
>>>>>> - // Sort the indexes in place using qsort
>>>>>> - // FIXME: (WRONGDEFINE) Need a better define for this!
>>>>>> -#ifdef __APPLE__
>>>>>> - ::qsort_r (&indexes[0], indexes.size(), sizeof(uint32_t), (void *)&m_symbols[0], Symtab::CompareSymbolValueByIndex);
>>>>>> -#else
>>>>>> - ::qsort_r (&indexes[0], indexes.size(), sizeof(uint32_t), CompareSymbolValueByIndexLinux, (void *)&m_symbols[0]);
>>>>>> -#endif
>>>>>> + // Sort the indexes in place using std::sort
>>>>>> + std::sort(indexes.begin(), indexes.end(), SymbolIndexComparator(m_symbols));
>>>>>>
>>>>>> // Remove any duplicates if requested
>>>>>> if (remove_duplicates)
>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>
>>>>
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