Re: [PATCH] perf stat: Add hint for SMI cost measurement

[Liang, Kan]

On 4/25/2019 1:47 PM, Ingo Molnar wrote:
> * Liang, Kan <kan.liang@xxxxxxxxxxxxxxx> wrote:
>
> > On 4/25/2019 2:39 AM, Ingo Molnar wrote:
> > > * kan.liang@xxxxxxxxxxxxxxx <kan.liang@xxxxxxxxxxxxxxx> wrote:
> > >
> > > > +static void smi_env_check(void)
> > > > +{
> > > > +	char *name;
> > > > +	size_t len;
> > > > +
> > > > +	if (sysfs__read_str(CPUIDLE_CUR_DRV, &name, &len)) {
> > > > +		pr_warning("Failed to check cstate status.\n");
> > >
> > > What a meaningless message. What did we want to do, what happened, and
> > > why did it fail?
> > >
> > > > +		return;
> > > > +	}
> > > > +
> > > > +	if (strncmp(name, "none", 4)) {
> > > > +		pr_warning("Cstate may cause drift between aperf and cycles. "
> > > > +			   "Please completely disable cstate, "
> > > > +			   "E.g. set idle=poll in grub\n");
> > >
> > > Please keep user-visible strings in the same form that the user sees
> > > them, i.e. in a single line.
> >
> > To avoid the line over 80 characters, the quoted string was split across
> > lines in the code. But the string is shown as a single line when it is
> > output for user.
> >
> > Are you suggesting to ignore the 80 characters rule when printing
> > user-visible strings?
> > Could you please confirm?
>
> What I'd suggest is split it up into multiple messages, or shorten the
> message. Small violations of col80 for user visible strings is fine (up
> to 100-120 columns I guess), but if the string is longer it's a clear
> sign that the syslog message it too long to begin ...

Sure, I will update the messages and send out V2.

Thanks,
Kan