LWN: Comments on "An interview with Linus Torvalds"

An interview with Linus Torvalds

Ekdikeo — 2003-07-12T18:48:32+00:00

Try 2.5.75. I just went from 2.5.73 to 2.5.75 and was -totally- amazed by the difference. I had a ton of broken modules before, all of them compiled flawlessly. I couldn't insert any modules before (and yes, I had the correct mod tools) because dependencies couldn't be resolved (i presume because half my modules wouldn't compile) .. they all compile, and insert. it's beautiful. it's like butta.

Also, my memory usage on startup went from like 65MB to 20MB, and after loading X (with fvwm2) I still have about 70MB free on a 128MB system.

The response time is INCREDIBLE compared to 2.4 and previous 2.5 series.

Also, if you're running Debian, make sure that your X package is NOT set to nice the Xserver by -10. That improved response time in 2.4 and previous, but is actually a bad thing for the improved task schedulers in 2.5.

Does he follow LWN?

avik — 2003-07-08T17:24:21+00:00

One question I missed, do you read lwn?

Can't imagine how he keeps up if he doesn't :)

Emacs vs VI

lovelace — 2003-07-08T05:13:24+00:00

Actually, according to question 10 of the FAQ which someone else posted, it says he uses
Microemacs. Granted, ME isn't emacs or vi, but it seems to be a lot closer to emacs than vi
which would tend to suggest that he doesn't quite loathe emacs...

An interview with Linus Torvalds

daniel — 2003-07-04T01:51:26+00:00

"2.5 is horrible on the desktop - several users (myself included) so far have complained about sound skipping and jerky mouse and window movement"

Con Kolivas' interactivity patch fixes things up a great deal. It's now in 2.5.74-mm (Andrew Morton's kernel):

http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.5/2.5.74/2.5.74-mm1

Window dragging doesn't make sound skip any more. You can still make sound skip by scrolling in Mozilla, but Con's busy tweaking the patch. Before this, ogg playing on 2.5 was definitely painful, now it's tolerable. Expect more improvement in the not too distant future, especially if you keep testing and complaining :-)

definition of scalability

giraffedata — 2003-07-03T23:09:46+00:00

>Software that only scales up isn't very scalable

The wording here actually weakens a very good point. There is no such thing as "only scales up." That's like saying a property line only runs East. Scalable means the size can be big or small. If you make Linux work great on a large system and not on a small system, it doesn't scale up. It's always up.

Windows developers use non-Windows: no scandal

giraffedata — 2003-07-03T23:00:22+00:00

I don't think it says much that Windows engineers and admins use something other than Windows at home. It says Windows isn't oriented towards computer geeks. That's OK -- there's a huge market for Windows among non-geeks.

Male gynecologists probably develop a lot of things they don't use at home.

little systems

iabervon — 2003-07-03T22:55:41+00:00

A lot of the big system things are for reducing overhead, which is important when you've got a ton of processes (e.g.) and limited low memory, but also important when you've got some processes and very little total memory.

Clustering, for now, seems to work fine without changing the mainline kernel. It's possible that a solution will turn up which is more generally applicable, but, presently, building the hardware for a cluster is enough of an effort that the software aspects aren't that big a deal.

A lot of SMP things are now moving to per-processor variables, which gives you a lot of the benefits of per-processor kernels without a lot of the difficulty. Of course, some locks disappear when you compile for uniprocessor, and other locks are actually helpful for handling pre-emption, which is significant for embedded devices and desktops. It's just necessary to put thought into designing locking schemes, and not just throw locks everywhere.

From my amateur viewpoint...

danielf — 2003-07-03T16:07:09+00:00

I know many Windows admins at the senior level that use Linux at home :)

An interview with Linus Torvalds

proski — 2003-07-03T14:38:29+00:00

The switch exists already. It's called CONFIG_PREEMPT. If you care about jerky mouse, enable it. If you care about average speed, disable it.

An interview with Linus Torvalds

StevenCole — 2003-07-03T01:07:55+00:00

My experience with recent 2.5.x kernels for desktop use has been different. After several hours of heavy use, the 2.5 systems remain responsive, while the default kernels of RedHat 9 and Mandrake 9.1 become less responsive and make more use of swap. The mouse with 2.5 is much slower and I have to increase the pointer acceleration in KDE to make 2.5 useable. Your mileage does vary, and it's important that your issues get resolved.

Linus's dual AMD box from two years ago was assembled about 3 blocks from where I lived at the time. Nice machine then, nice machine now. Recently he's been using a 4-way desktop (according to a post on lkml), so he may not notice some regressions which are evident to others.

As Linus pointed out above:

...it's always hard to anticipate everything that pops up when a lot of new people start moving over from 2.4.x to 2.6.x.

Desktop useability will always be one of the most important things. Maybe Linus will announce 2.6.0-test1 at OLS next month, which will likely increase the number of testers substantially. I hope those testers having difficulties will complain loudly and intelligently enough to be heard.

As mbp noted, distributers can and do provide differing kernels for differing purposes, but this can and should only be carried so far. If the core code diverges too far from what is optimal for desktop use, then maintaining those different kernels will become an increasing burden.

An interview with Linus Torvalds

mbp — 2003-07-03T00:32:34+00:00

Well, to some extent this can be done by setting different options or merging non-Linus patches. Distributors are probably the right people to do this, not Linus. For example, RedHat give you a different kernel in the desktop-oriented install rather than the server-oriented install, and Gentoo by default uses a 2.4 with patches for better interactive/desktop performance. End users should not need to recompile.

We don't want too much divergence though. Eventually it ought to be possible to have a single codebase that builds for both systems, but as development proceeds different patches can favor one over the other.

An interview with Linus Torvalds

Lovechild — 2003-07-02T23:38:13+00:00

2.5 is horrible on the desktop - several users (myself included) so far have complained about sound skipping and jerky mouse and window movement.

And to my horror it seems that the hackers are still aiming for the sky, and everytime someone points out a possible improvement towards desktop users, somebody yells database, server, etc. and the idea is never tested.

Maybe it's time to make a toplevel switch to desktop/server - so we could get the best of both worlds in the source and let the user decide which to use at compile time. This would mean that if DESKTOP is set then CFQ replaces AS as the default IO scheduler, Different process scheduler setting is used, and other tweaking. I would hate for Linus to decide that the desktop was to be left to vendors to handle in their own trees.

little systems / BIG systems

StevenCole — 2003-07-02T22:05:42+00:00

having a kernel run on each proc or quad rather than 1 kernel is a much better way I think

This is probably harder to do than it seems, and it seems pretty difficult. For some light reading, see A Practical Approach to Linux Clusters on SMP Hardware by Karim Yaghmour or Scaling Linux with (partially) CC Clusters by Larry McVoy.

This talk, Linux Scalability for Large NUMA Systems, looks like it will be interesting, along with many others.

Since Jon will be there, perhaps he can provide a nice review.

An interview with Linus Torvalds

johnny — 2003-07-02T20:31:52+00:00

Linus loathes Emacs. I think he uses a modified version of vi.

little systems

jimi — 2003-07-02T19:40:47+00:00

Linus has stated previously that scalability goes both ways: large systems and small systems. Software that only scales up isn't very scalable, it must also scale down. So I think he and others are aware of trying to make things work well in very small systems (in fact, newer kernels often have increased performance on the same old hardware).

As for SMP, the locking improves constantly. But the best solution probably isn't to have a kernel running on each CPU. Interrupts from the same device aren't always received on the same CPU. Imagine trying to coordinate interrupt processing between seperate kernels. Fouther problems arise in memory management, particularly on non-NUMA systems (which kernel owns which memory? How do you keep one kernel from stomping on the memory of another? How do you allocate large chunks of memory for an app? Let the kernels fight it out? Does that mean that an app would be tied to one kernel?)

An interview with Linus Torvalds

xach — 2003-07-02T18:24:18+00:00

This is in the unofficial FAQ.

An interview with Linus Torvalds

torsten — 2003-07-02T18:04:17+00:00

Amazing. You have interviewed the top programmer in my [Linux} world, and you fail to ask the most important question.

Vi or Emacs?

little systems

johnjones — 2003-07-02T16:25:53+00:00

how about 8MB of RAM and 8MB of ROM do people worry about this ?
they need too its what phones run
(e.g. I dont see people doing things like XIP as much as people worry about no. of threads )

and can someone please sort out clustering...
2 best solutions I can see are
being able to move process's over the wire( network or within the local system for mem
locality and resource util)
doing the message thing ( MPI etc )

as more and more SMP systems come about the locking is going to turn into a solaris
nightmare unless people do somthing soon. having a kernel run on each proc or quad rather
than 1 kernel is a much better way I think... Having a solution in mainline kernel would help
things and I belive it's better to have both of these solutions.

regards

John Jones

From my amateur viewpoint...

flewellyn — 2003-07-02T08:34:03+00:00

...it seems to me that the best developers of software are those who use it themselves. Witness Linux, the GNU system, XFree86, KDE, GNOME, GIMP, etc., etc., etc. The people working on those projects care about what they're doing, because they will use the tools themselves.

On the other hand, I hear tell from spies inside Microsoft that many Windows developers actually use *nix on their home machines. That should tell us something. :-)

An interview with Linus Torvalds

jarek — 2003-07-02T06:40:15+00:00

I much prefer to take a reactionary stance and see what people actually complain and care about, rather than having a "5-year plan".
I honestly think this state of mind is what has made Linux the success story it is. It speaks volumes about "satifiying customer needs" as the business world would put it. As far as I see, Linus never wanted to write a Unix clone, he just wanted to HAVE a Unix-like OS to run on his 386.

SCO is a rabid rat frothing at the mouth

rjamestaylor — 2003-07-02T05:33:25+00:00

Worth the price of admission.