Re: [PATCH 1/7] x86: Limit the number of processor bootup messages

Ingo Molnar
2009-11-13T09:54:13Z

* Mike Travis <travis@sgi.com> wrote:

>
>
> Ingo Molnar wrote:
> >* Mike Travis <travis@sgi.com> wrote:
> >
> >>--- linux.orig/arch/x86/kernel/smpboot.c
> >>+++ linux/arch/x86/kernel/smpboot.c
> >>@@ -442,6 +442,84 @@
> >> return c->llc_shared_map;
> >> }
> >>+/* Summarize Processor Information */
> >>+static void __init summarize_cpu_info(void)
> >>+{
> >>+ cpumask_var_t cpulist, cpusdone;
> >>+ int cpu;
> >>+ int err = 0;
> >>+
> >>+ if (!alloc_cpumask_var(&cpulist, GFP_KERNEL))
> >>+ err = 1;
> >>+ else if (!alloc_cpumask_var(&cpusdone, GFP_KERNEL)) {
> >>+ free_cpumask_var(cpulist);
> >>+ err = 1;
> >>+ }
> >>+ if (err) {
> >>+ printk(KERN_INFO "Can't print processor summaries\n");
> >>+ return;
> >>+ }
> >>+
> >>+ cpumask_clear(cpusdone);
> >>+ for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
> >>+ struct cpuinfo_x86 *c;
> >>+ char buf[128];
> >>+ int ncpu, len;
> >>+ unsigned long minlpj, maxlpj, avglpj = 0;
> >>+
> >>+ /* skip if cpu has already been displayed */
> >>+ if (cpumask_test_cpu(cpu, cpusdone))
> >>+ continue;
> >>+
> >>+ c = &cpu_data(cpu);
> >>+ minlpj = ULONG_MAX;
> >>+ maxlpj = 0;
> >>+
> >>+ cpumask_clear(cpulist);
> >>+
> >>+ /* collate all cpus with same specifics */
> >>+ for (ncpu = cpu; ncpu < nr_cpu_ids; ncpu++) {
> >>+ struct cpuinfo_x86 *n = &cpu_data(ncpu);
> >>+
> >>+ if (c->x86 != n->x86 ||
> >>+ c->x86_vendor != n->x86_vendor ||
> >>+ c->x86_model != n->x86_model ||
> >>+ c->x86_mask != n->x86_mask ||
> >>+ strcmp(c->x86_model_id, n->x86_model_id))
> >>+ continue;
> >>+
> >>+ cpumask_set_cpu(ncpu, cpulist);
> >>+ cpumask_set_cpu(ncpu, cpusdone);
> >>+
> >>+ if (cpu_data(ncpu).loops_per_jiffy < minlpj)
> >>+ minlpj = cpu_data(ncpu).loops_per_jiffy;
> >>+
> >>+ if (cpu_data(ncpu).loops_per_jiffy > maxlpj)
> >>+ maxlpj = cpu_data(ncpu).loops_per_jiffy;
> >>+
> >>+ avglpj += cpu_data(ncpu).loops_per_jiffy;
> >>+ }
> >>+
> >>+ len = cpulist_scnprintf(buf, sizeof(buf), cpulist);
> >>+ printk(KERN_INFO
> >>+ "Processor Information for CPUS: %s%s\n",
> >>+ buf, (len == sizeof(buf)-1) ? "..." : "");
> >>+
> >>+ printk(KERN_INFO);
> >>+ print_cpu_info(c);
> >>+
> >>+ avglpj /= cpumask_weight(cpulist);
> >>+ printk(KERN_INFO "BogoMIPS: MIN %lu.%02lu (%lu) "
> >>+ "AVG %lu.%02lu (%lu) MAX %lu.%02lu (%lu)\n",
> >>+ minlpj/(500000/HZ), (minlpj/(5000/HZ)) % 100, minlpj,
> >>+ avglpj/(500000/HZ), (avglpj/(5000/HZ)) % 100, avglpj,
> >>+ maxlpj/(500000/HZ), (maxlpj/(5000/HZ)) % 100, maxlpj);
> >>+ }
> >>+
> >>+ free_cpumask_var(cpusdone);
> >>+ free_cpumask_var(cpulist);
> >>+}
> >>+
> >
> >Sigh, that's _way_ too complex.
> >
> >If you cannot print it in a summarized way without carrying over
> >stupid state like bitmaps then please do the simple and obvious,
> >and print:
> >
> >booting CPUs: #0 #1 #2 #3 #4 #5 #6 ...
>
> That is almost exactly what it does. [...]

You are missing my point i think, which is that we dont want the 76
lines long summarize_cpu_info() complexity during bootup. Lets keep it
_very_ simple and zap excessive messages - like DaveJ's patch did.

Ingo