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

[Richard Henderson]

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~