[LLVMdev] [LNT][Patch] Bug 16261 - lnt incorrectly builds timeit-target when one is using a simulator

[Reed Kotler]

Okay to push this change?

On 07/23/2013 05:17 PM, reed kotler wrote:
> Hi Daniel,
>
> In this case we are not using lnt under Qemu user mode for benchmarking;
> just as a way to run test-suite to test whether the code is correct.
>
> Qemu user mode emulates target instructions, but when it gets a Unix
> Kernel trap, it uses the host to emulate those.
>
> For example, file I/O.
>
> It is possible to run target timeit under qemu and let it launch the app
> or a wrapper.
> (But it is more limited as to what can be done here under qemu vs under
> the host OS directly).
>
> For time functions, it is also going to use the host to emulate those.
>
> So whether timeit is running under qemu or directly on the host, the
> answers regarding time will be the same.
>
> But running timeit under qemu will be much slower as far as elapsed time
> than running it on the host directly.
>
> We would also need to add some new mechanism to Lnt or the makefiles to
> also wrap timeit.
>
> Reed
>
>
> On 07/23/2013 02:19 PM, Daniel Dunbar wrote:
>> Wouldn't it be a more accurate simulation to run timeit-target under
>> the emulator as well? Or is that too much to ask?
>>
>>  - Daniel
>>
>>
>> On Mon, Jul 22, 2013 at 6:47 PM, Reed Kotler
>> <rkotler-8NJIiSa5LzA at public.gmane.org
>> <mailto:rkotler-8NJIiSa5LzA at public.gmane.org>> wrote:
>>
>>
>>
>>     Just to clarify:
>>
>>     this is when tests are run under USER mode qemu.
>>
>>
>>     On 07/22/2013 04:09 PM, Doug Gilmore wrote:
>>
>>         I attached a patch to lnt that addresses this issue.
>>
>>         The patch adds the --host-compile-tools option, which when
>>         specified,
>>         forces compilation of the tools for execution on the host.
>>
>>         This allows lnt to be used for correctness testing when the tests
>>         are run under QEMU.
>>
>>         Comments?
>>
>>         Doug
>>
>>
>>
>>
>>
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