AernaLingus [any]

Original Declassified article

I think you meant to post this in a thread about MGS

Thanks liberal justices, very cool!

Original Phoronix article which has all the individual benchmarks—weird that they didn’t link to it

There’s a variable that contains the number of cores (called cpus) which is hardcoded to max out at 8, but it doesn’t mean that cores aren’t utilized beyond 8 cores–it just means that the scheduling scaling factor will not change in either the linear or logarithmic case once you go above that number:

/*
 * Increase the granularity value when there are more CPUs,
 * because with more CPUs the 'effective latency' as visible
 * to users decreases. But the relationship is not linear,
 * so pick a second-best guess by going with the log2 of the
 * number of CPUs.
 *
 * This idea comes from the SD scheduler of Con Kolivas:
 */
static unsigned int get_update_sysctl_factor(void)
{
	unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8);
	unsigned int factor;

	switch (sysctl_sched_tunable_scaling) {
	case SCHED_TUNABLESCALING_NONE:
		factor = 1;
		break;
	case SCHED_TUNABLESCALING_LINEAR:
		factor = cpus;
		break;
	case SCHED_TUNABLESCALING_LOG:
	default:
		factor = 1 + ilog2(cpus);
		break;
	}

	return factor;
}

The core claim is this:

It’s problematic that the kernel was hardcoded to a maximum of 8 cores (scaling factor of 4). It can’t be good to reschedule hundreds of tasks every few milliseconds, maybe on a different core, maybe on a different die. It can’t be good for performance and cache locality.

On this point, I have no idea (hope someone more knowledgeable will weigh in). But I’d say the headline is misleading at best.

Real babies in incubators

Imaginary babies in incubators

Holy shit. I’ll be honest, having quit using reddit for daily browsing and simply relegating it to its main productive purpose of “usable Google results,” I kind of assumed that the outrage over the API pricing ultimately didn’t have much of an effect. But this data is nuts. I guess it goes to show the effect that alienating power users can have on a site that’s so power-user driven, where a fraction of users even comment and a tiny fraction of that fraction posts content and an even tinier fraction of that tiny fraction moderates to keep things running smoothly.