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

Ingo Molnar
2009-11-12T18:10:16Z

* 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 ...

It's a really long line with 4096 CPUs but that's not a big problem - on
most systems it will look sane.

Ingo