Re: [PATCH 2/8] perf metrics: fix parse errors in cascade lake metrics

[Jin, Yao]

Hi Jiri,

Bisected to this commit which introduced the regression.

26226a97724d ("perf expr: Move expr lexer to flex")

Would you like to look at that?

Thanks
Jin Yao

On 4/23/2020 9:08 AM, Jin, Yao wrote:
> On 4/23/2020 12:18 AM, Ian Rogers wrote:
> > On Wed, Apr 22, 2020 at 8:34 AM Ian Rogers <irogers@xxxxxxxxxx> wrote:
> > > On Wed, Apr 22, 2020 at 7:38 AM Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
> > > > On Wed, Apr 22, 2020 at 12:48:03AM -0700, Ian Rogers wrote:
> > > > > Remove over escaping with \\.
> > > > > Remove extraneous if 1 if 0 == 1 else 0 else 0.
> > > >
> > > > So where do these parse errors happen exactly? Some earlier
> > > > patches introduced them as regressions?
> > >
> > > I'll work to track down a Fixes tag. I can repro the Skylakex errors
> > > without the test in this series, by doing:
> > >
> > > $ perf stat -M DRAM_Read_Latency sleep 1
> > > Error:
> > > The sys_perf_event_open() syscall returned with 22 (Invalid argument)
> > > for event (cha/event=0x36\,uma
> > > sk=0x21/).
> > > /bin/dmesg | grep -i perf may provide additional information.
>
> I also think some patches introduced this regression. When we rollback 
> to commit 61ec07f5917e (perf vendor events intel: Update all the Intel 
> JSON metrics from TMAM 3.6.), there is no this error on CLX.
>
> Thanks
> Jin Yao
>
> > > This was just the escaping issue. I'm less clear on the other cascade
> > > lake issue, and it is a bit more work for me to test on cascade lake.
> > > What is "if 1 if 0 == 1 else 0 else 0" trying to do? Perhaps hunting
> > > for the Fixes will let me know, but it looks like a copy-paste error.
> > >
> > > > The original metrics worked without parse errors as far as I know.
> > >
> > > The skylake issue above repros on 5.2.17 and so it seems like it is
> > > broken for a while. The test in this series will prevent this in the
> > > future, but without this patch that test fails.
> >
> > The parse errors were introduced with the metrics, so they've never 
> > worked:
> > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=fd5500989c8f3c3944ac0a144be04bae2506f7ba 
> >
> >
> > I will send out a v2 with Fixes in the commit message but wanted to
> > wait in case there was any more feedback. In particular the fixes to
> > the new test and expr parser lex code. The lex code wasn't broken at
> > the time the metrics were added and should be working again after this
> > patch set.
> >
> > Thanks,
> > Ian
> >
> > > > If it fixes something earlier it would need Fixes: tags.
> > >
> > > Working on it. Thanks for the input!
> > >
> > > Ian
> > >
> > > > -Andi