Severe performance degradation on Linux

[Michael Meeks]

On Tue, 2015-01-06 at 15:20 +0100, Maarten Hoes wrote:
> Well I tried this, and it produced a file of a whopping 383087 lines
> and 30 MB.

	That is expected.

>  I wouldnt expect any sane person to look through all of that in its
> entirety on a page by page basis. 
> ;)

	Hit page-down in 'less' - and when you see the time-stamp 'jump' (ie.
we missed 20 seconds ;-) on the left - then that's the interesting bit.

> Are the large amounts of 'futex(FUTEX_WAIT_PRIVATE) /
> futex(FUTEX_WAKE_PRIVATE)' expected behavior in this case ?

	Yes - quite expected - and yes we take locks and release them just for
fun all over the place: then again, we shouldn't take contended locks a
lot so should avoid the syscall there mostly which is in itself odd -
but I doubt that that is related to your problem.

	ATB,

		Michael.

-- 
 michael.meeks at collabora.com  <><, Pseudo Engineer, itinerant idiot