[Lldb-commits] [lldb] r105834 - in /lldb/trunk: include/lldb/Symbol/Symtab.h source/Symbol/Symtab.cpp

[Owen Anderson]

Assuming you meant "purge" at the command line, I still measure 0.052s for -Os with std::stable_sort.  If there's nothing else you want me to test,  I'll go ahead and commit it with that.

--Owen

On Jun 16, 2010, at 10:19 AM, Greg Clayton wrote:

> Great news. Try testing this same stuff after a "purge" (clear the file caches). The "purge" is not a great test, but it gives you a bit of an idea of how things would perform if nothing was in the file cache...
> 
> If things turn out the same as before, feel free to checkin the std::stable_sort fix.
> 
> Greg Clayton
> 
> On Jun 16, 2010, at 10:04 AM, Owen Anderson wrote:
> 
>> OK, I just performed these measurements on 64-bit 10.6, with both -Os and -O3 builds of lldb.  In both cases, std::sort was on the order of 50% slower than qsort_r:
>> 
>>                    -Os      -O3
>> std::sort          0.118s   0.103s       
>> qsort_r            0.077s   0.078s
>> 
>> However, here's the interesting part:
>> 
>> std::stable_sort   0.051s   0.048s
>> 
>> So, it looks like the symbol tables are already mostly sorted, and a simple insertion sort is able to "complete" the sort quickly.  FWIW, this would also be a good place to apply TimSort or some other heuristic sort.
>> 
>> --Owen
>> 
>> 
>> On Jun 16, 2010, at 9:27 AM, Greg Clayton wrote:
>> 
>>> 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.
>>> 
>> 
>> 
> 

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