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

[Ian Rogers]

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.
>
> 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