Hyperthreading

Posted May 9, 2013 13:14 UTC (Thu) by sheepdestroyer (guest, #54968)
In reply to: Hyperthreading by bgmarete
Parent article: (Nearly) full tickless operation in 3.10

Also interested by that particular issue. Got a SandyBridge ultra-portable so 2 "real" cores + 2 HT and would like to know how much if any power save should i expect?

Hyperthreading

Posted May 9, 2013 15:59 UTC (Thu) by drago01 (subscriber, #50715) [Link] (5 responses)

I doubt this will get you any noticeable power savings if at all. The most interesting part for power saving is the idle part which is already handled by CONFIG_NO_HZ

Hyperthreading

Posted May 10, 2013 8:43 UTC (Fri) by akeane (guest, #85436) [Link] (4 responses)

The config option should be called: CONFIG_WINDOWS_311

Really, "cooperative" multi-tasking?

Really?

Really...

Hyperthreading

Posted May 10, 2013 18:59 UTC (Fri) by PaulMcKenney (✭ supporter ✭, #9624) [Link]

Cute, but inaccurate. ;-)

If there is only one CPU-bound task runnable on a given CPU, there is no point in any scheduling decisions.

If there are multiple tasks runnable on a given CPU, and if the currently running task is CPU-bound, then there is no point in any scheduling decisions until the next timeslice.

Of course, things might change in the meantime, but in that case, this CPU will receive an interrupt and can therefore adjust as appropriate at that point in time.

Hyperthreading

Posted May 13, 2013 21:46 UTC (Mon) by chloe_zen (guest, #8258) [Link] (2 responses)

I think you haven't been keeping up with current events (no pun intended); event-driven loops in a single OS thread are the New Way of getting the most I/O through a CPU. This is a realistically useful optimization.

Hyperthreading

Posted May 20, 2013 23:13 UTC (Mon) by marcH (subscriber, #57642) [Link] (1 responses)

So, ticks to look some day as outdated as polling?

ticks vs. polling

Posted May 21, 2013 7:49 UTC (Tue) by cladisch (✭ supporter ✭, #50193) [Link]

> ticks to look some day as outdated as polling?

Polling is regularly checking the status, just because something that needs handling might have happened.

Ticks are polling.