Messages in this thread | | | Date | Thu, 25 Apr 2019 08:39:10 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] perf stat: Add hint for SMI cost measurement |
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* kan.liang@linux.intel.com <kan.liang@linux.intel.com> 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.
By doing that you'll also note a capitalization error.
Also what does 'Cstate may cause drift' mean? What aspect of cstates causes the drift - entering/exiting deeper cstates that are not C0? If so then say so.
Thanks,
Ingo
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