2015-12-11 10:49:44

by Pavel Machek

Subject: 4.4-rc: 28 bioset threads on small notebook

Hi!

I know it is normal to spawn 8 threads for every single function,

root 1069 0.0 0.0 0 0 ? S Dec08 0:00
[scsi_eh_0]
root 1070 0.0 0.0 0 0 ? S< Dec08 0:00
[scsi_tmf_0]
root 1073 0.0 0.0 0 0 ? S Dec08 0:00
[scsi_eh_1]
root 1074 0.0 0.0 0 0 ? S< Dec08 0:00
[scsi_tmf_1]
root 1077 0.0 0.0 0 0 ? S Dec08 0:00
[scsi_eh_2]
root 1078 0.0 0.0 0 0 ? S< Dec08 0:00
[scsi_tmf_2]
root 1081 0.0 0.0 0 0 ? S Dec08 0:00
[scsi_eh_3]
root 1082 0.0 0.0 0 0 ? S< Dec08 0:00
[scsi_tmf_3]
root 1085 0.0 0.0 0 0 ? S Dec08 0:00
[scsi_eh_4]
root 1087 0.0 0.0 0 0 ? S< Dec08 0:00
[scsi_tmf_4]
root 1101 0.0 0.0 0 0 ? S Dec08 0:00
[scsi_eh_5]
root 1102 0.0 0.0 0 0 ? S< Dec08 0:00
[scsi_tmf_5]
root 2741 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2742 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2743 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2744 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2745 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2746 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2747 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]
root 2748 0.0 0.0 0 0 ? S Dec08 0:00 [nfsd]


but 28 threads?

root 974 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 977 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 980 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 983 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 986 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 989 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 992 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 995 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1000 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1002 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1003 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1004 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1005 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1006 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1007 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1008 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1009 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1010 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1011 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1012 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1013 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1014 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1015 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
root 1016 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]

?

I'm not even using btrfs.

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

2015-12-11 14:08:44

by Mike Snitzer

Subject: Re: 4.4-rc: 28 bioset threads on small notebook

On Fri, Dec 11 2015 at 5:49am -0500,
Pavel Machek <[email protected]> wrote:

> Hi!
>
> I know it is normal to spawn 8 threads for every single function,
...
> but 28 threads?
>
> root 974 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
...

How many physical block devices do you have?

DM is doing its part to not contribute to this:
dbba42d8a ("dm: eliminate unused "bioset" process for each bio-based DM device")

(but yeah, all these extra 'bioset' threads aren't ideal)

2015-12-11 17:14:42

by Pavel Machek

Subject: Re: 4.4-rc: 28 bioset threads on small notebook

Hi!

> > Hi!
> >
> > I know it is normal to spawn 8 threads for every single function,
> ...
> > but 28 threads?
> >
> > root 974 0.0 0.0 0 0 ? S< Dec08 0:00 [bioset]
> ...
>
> How many physical block devices do you have?
>
> DM is doing its part to not contribute to this:
> dbba42d8a ("dm: eliminate unused "bioset" process for each bio-based DM device")
>
> (but yeah, all these extra 'bioset' threads aren't ideal)

Thinkpad X60. One sda, and on SD card slot. I guess I did use the SD
card from boot, and did few suspend/resume cycles...
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html