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

[Jiri Olsa]

On Thu, Apr 23, 2020 at 12:10:36PM +0200, Jiri Olsa wrote:
> On Thu, Apr 23, 2020 at 03:51:18PM +0800, Jin, Yao wrote:
> > Hi Ian,
> > 
> > On 4/23/2020 2:09 PM, Ian Rogers wrote:
> > > On Wed, Apr 22, 2020 at 10:54 PM Jin, Yao <yao.jin@xxxxxxxxxxxxxxx> wrote:
> > > > 
> > > > 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?
> > > 
> > > Hi Jin,
> > > 
> > > that commit breaks parsing of things like ','. See fixes in this patch
> > > set such as:
> > > https://lore.kernel.org/lkml/20200422220430.254014-5-irogers@xxxxxxxxxx/
> > > Fixing the lex issues then exposes other bugs that need to be
> > > corrected in the json. I've added Fixes to the commit message of:
> > > https://lore.kernel.org/lkml/20200422220430.254014-3-irogers@xxxxxxxxxx/
> > > https://lore.kernel.org/lkml/20200422220430.254014-4-irogers@xxxxxxxxxx/
> > > and would be glad of a review. If we can land:
> > > https://lore.kernel.org/lkml/20200422220430.254014-12-irogers@xxxxxxxxxx/
> > > then expr as the source of parse errors can go away :-) The next
> > > problem is the parse events code, but some of that logic is dependent
> > > on the machine it is running on. It'd be good to add a test that
> > > parsed events code can handle the events in metrics too, filtering out
> > > things like duration_time that are special to metrics.
> > > 
> > > Thanks,
> > > Ian
> > > 
> > 
> > Only with the fix
> > "https://lore.kernel.org/lkml/20200422220430.254014-5-irogers@xxxxxxxxxx/";
> > (without other json modifications), the issue was still there.
> > 
> > localhost:~ # perf stat -M DRAM_Read_Latency
> > event syntax error:
> > '../event=0x36,,umask=0x21/,cha/event=0x35,cha_0/event=0x0/}:W,duration_time'
> >                                   \___ parser error
> > 
> >  Usage: perf stat [<options>] [<command>]
> > 
> >     -M, --metrics <metric/metric group list>
> >                           monitor specified metrics or metric groups
> > (separated by ,)
> 
> hum, I don't have that metric, is there another example of broken metric?
> 
> [jolsa@krava perf]$ sudo ./perf stat -M DRAM_Read_Latency
> Cannot find metric or group `DRAM_Read_Latency'
> 
> > 
> > So you added other commits which changed the json to let the parse work. But
> > I don't know if we have to do with this way because it should be a
> > regression issue.
> > 
> > In my opinion, we'd better fix the issue in 26226a97724d ("perf expr: Move
> > expr lexer to flex") and try not to change the json if possible.
> 
> yea, that change definitely had a potential of breaking things ;-)
> but it should be easy to fix them
> 
> I'll go through the v3 of the patchset

ok, there's v2 now ;-)

jirka