Re: [PATCH v13 04/10] accel/tcg: add jit stats and time to TBStatistics

[Richard Henderson <richard.henderson@linaro.org>]

On 6/1/23 05:48, Wu, Fei wrote:
> On 6/1/2023 7:51 PM, Alex Bennée wrote:
>>
>> "Wu, Fei" <fei2.wu@intel.com> writes:
>>
>>> On 5/30/2023 6:08 PM, Alex Bennée wrote:
>>>>
>>>> "Wu, Fei" <fei2.wu@intel.com> writes:
>>>>
>>>>> On 5/30/2023 1:01 PM, Wu, Fei wrote:
>>>>>> On 5/30/2023 12:07 PM, Richard Henderson wrote:
>>>>>>> On 5/29/23 04:49, Fei Wu wrote:
>> <snip>
>>> ----------------
>>> IN:
>>> Priv: 1; Virt: 0
>>>
>>> 0xffffffff800abe14:  864a              mv                      a2,s2
>>> 0xffffffff800abe16:  85ce              mv                      a1,s3
>>> 0xffffffff800abe18:  8526              mv                      a0,s1
>>> 0xffffffff800abe1a:  46bd              addi                    a3,zero,15
>>> 0xffffffff800abe1c:  fffff097          auipc                   ra,-4096
>>>                # 0xffffffff800aae1c
>>> 0xffffffff800abe20:  cc0080e7          jalr                    ra,ra,-832
>>> ------------------------------
>>>
>>> Look at the tb with phys:0x2abe14, although the first time IR takes
>>> 75274ns, but in the second command we can see it takes much less time
>>> (Note IR time is accumulated).
>>>
>>> So if the time for the same TB is not consistent, and the deviation
>>> could be dominated by system events such as memory allocation instead of
>>> codegen itself (?), I think it's less useful.
>>>
>>> Alex, regarding dropping time profile, do you mean remove TB_JIT_TIME
>>> completely?
>>
>> I think so - perf would do a better job of separating system events from
>> the core code as it has better visibility of the whole system.
>>
> OK, got it.
> 
> Richard, can we reach the agreement here? If yes, I will remove
> TB_JIT_TIME and all the time stuffs (dev_time, cpu_exec_time)
> completely. We can still add it back if it proves to be useful. The only
> concern is that tbstats replaces CONFIG_PROFILER but drops this function
> from it.

Yes, I'm quite happy to drop all of the time stuff.


r~