[LLVMdev] google heap profile

[Daniel Dunbar]

dtrace can also be a useful tool for validating or investigating some
of the numbers.

 - Daniel

On Fri, Nov 11, 2011 at 11:49 AM, Chandler Carruth <chandlerc at google.com> wrote:
> On Fri, Nov 11, 2011 at 11:45 AM, reed kotler <rkotler at mips.com> wrote:
>>
>> On 11/11/2011 11:39 AM, Chandler Carruth wrote:
>>
>> On Fri, Nov 11, 2011 at 11:36 AM, reed kotler <rkotler at mips.com> wrote:
>>>
>>> Is anybody using the google heap profiler to analyze clang/llvm ??
>>>
>>> http://google-perftools.googlecode.com/svn/trunk/doc/heapprofile.html
>>>
>>> If so, do you know how to modify the build scripts to enable that.
>>>
>>> Tia.
>>
>> I have tried to use this in the past without terribly much success.
>> Instead, I usually use Valgrind to analyze the allocation patterns:
>> http://valgrind.org/docs/manual/ms-manual.html
>>
>> I've been using valgrind too. It seems to work fine.
>>
>> I need to independently validate some numbers though because the answer
>> has big implications for some planning we are doing.
>
> In the past I have use the Google perf tools by using LDPRELOAD to inject
> them into the running binary.
> Note that the subprocess-ing can impact things, you need to drop down to the
> cc1 invocation first.
> Still, I have found that the heap profiling in these tools is strictly
> inferior to massif. I'd trust it. There are lots of flags you can give to
> massif to cause it to be very very accurate despite being quite slow. Do
> those help?
> You can also look at the '-print-stats' option (or something like that)
> which prints out internal allocation stats for various significant parts of
> Clang, and might be able to correlate the two to gain confidence.
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