Cheating: Not just for Microsoft anymore [LWN.net]

Cheating: Not just for Microsoft anymore

Posted Oct 3, 2008 19:07 UTC (Fri) by farnz (guest, #17727)
In reply to: Cheating: Not just for Microsoft anymore by Janne
Parent article: LPC: Booting Linux in five seconds

You're missing a lot in your example timeline; let me rework it the way it would actually happen:

My wife is in the kitchen, and finds that she's got ingredients she'd like to use for supper, but she'd like to use them for something different to her normal cooking style.
She goes into the living room, and fires up my laptop.
She wait, knowing that as soon as it's running, she'll want to log in.
System boots. She logs in.
She waits, knowing that as soon as it's logged in, she'll want to run Firefox.
She clicks on the Firefox icon on her desktop.
She waits, knowing that Firefox will come up maximised. Her mouse is hovering over where the bookmark for the recipe site she usually uses (when on my laptop, not hers - she has a much more complex set up on her own machine) will be.
Firefox starts enough that she can click on that bookmark. If the network is not running by this point, things are broken for her, as she can't go to the ingredient search and work out she can cook with the contents of our fridge.
She finds a recipe she'd like to try, and prints it - she likes to make notes on paper of changes she makes to a recipe while cooking, so that she can remember them easily later.

Looking at that timeline, one important thing is clear - she has already decided to go to a particular bookmarked website before she touches the power button. All the time taken between her pushing the power button and the website displaying is wasted by the computer. Thus, the only time the OS has free to waste is the time taken by Firefox to start up after the OS has started.

Secondly, note that Firefox's start up will be slowed down if the computer is also trying to bring up the network, start printing services and generally do other things at the same time. It's incredibly hard to accurately judge how much idle time you have around application start time.

Finally, in my experience, services are not delayed after thinking about use cases. Instead, the delay is based on getting the bare minimum up and running to let me log in, with functionality taking a while to come up after that. Making the challenge "get to idle in 5 seconds" leaves room for someone to come in later, and build on that work to get a "get to usable in 4 seconds, idle in 6", or even a "get to usable in under a second, but idle takes 6 seconds".

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Cheating: Not just for Microsoft anymore

Posted Oct 3, 2008 19:37 UTC (Fri) by Janne (guest, #40891) [Link]

In your example your wife would have to wait for few second for the network to become functional. Im sorry, but I don't really see that as a big issue. Especially considering the huge benefits users would get in "normal" use-cases.

You are describing a situation where the user is twitching to do something with the computer. Where the user even pre-positions the mouse in order to be able to do stuff as fast as possible. Those cases are very, very rare. Normal users do NOT work like that. Normally people don't start their computers thinking "OMG, I need to get online NOW!". And even if they did, the fact that the system boots in 5 seconds, means that they could get online a lot faster than with "normal" boot-sequence.

That said, I don't really understand the complaing about networking. My OpenSUSE-laptop takes ages to boot. And after it finally get to the desktop, it STILL spends few seconds connecting to the network! It would be A LOT better if it booted in 5 seconds, and then spend few seconds connecting to the network.

It makes sense to exclude networking from this experiment, since connecting to the network is not really part of what we call "booting". It's not up to your computer, it's basically being held back by the network. And hacking the boot-sequence of your computer does not touch your network in any shape or form. Network is completely outside the scope of this test. And just because you do not have working networking for few seconds does not mean that the computer is not usable. And still, the "normal" distros are just as slow as far as networking is concerned, so there are no drawbacks in this experiment, as far as networking is concerned.

So how would your wife benefit if the recipe-machine was using Ubuntu (for example)? Instead of booting in 5 seconds, the machine would boot in 45 seconds. Even if you had fully working networking after that 45 seconds (you wouldn't), it would still take about 30 seconds longer to get online than with this fast booting.

"Secondly, note that Firefox's start up will be slowed down if the computer is also trying to bring up the network"

Starting FIrefox taxes the HD and the CPU. Neither of those are taxed when your NIC is getting an IP-address.

"start printing services"

That could be started when the user actually wants to print. Why should we sit around, twiddling our thumbs, when the system starts printing-subsystem, even though the times we print are few and far between?

Cheating: Not just for Microsoft anymore

Posted Oct 4, 2008 11:11 UTC (Sat) by farnz (guest, #17727) [Link]

Then you're missing the entire point of the exercise - why does she have to wait 45 seconds for the OS to boot? Why should she be waiting up to a minute for things to be ready to use? Why can't she turn the computer on and use it immediately?In short, why is using a computer with a 1.83GHz Core 2 Duo and 4GB of RAM full of delays, when using an IPTV set top box with typically 100MHz CPU and 32MB RAM is not? Granted, the tasks are different, but the computer is so much more powerful than the STB that it's a fair question.

The idea Arjan and Auke were working to is to set a hard challenge - a typical Linux distro takes 30 seconds to get to the same point, they chose 5 seconds - and remove all the obstacles. If you allow delayed service startup to not count, the danger is that you'll discount services that matter to users. Indeed, you're already trying to handwave away an important service for some use cases as "takes too long, and anyway users can wait"; this is exactly why someone doing the challenge must set a defined state in which boot is finished. Given the defined state, I can now look at it, compare it to my use cases, and say "yes, that's good enough", or "no, I need to work out how to fit WiFi startup into that 5 seconds".

Again, as I've said several times, you can go from "5 seconds power applied to idle and ready" to "3 seconds power applied to usable, 3 more seconds to idle", and that's a much easier task than going from "60 seconds power applied to idle" to "3 seconds power applied to usable, 120 more seconds to idle.

Plus, my experience of normal users is very different to yours - they don't have computers waiting and switched on, they don't start the computer up without a task in mind, they start the computer thinking "Do I have any e-mail waiting?", "Can I look up a recipe to use lemon sole, potatoes and tomatoes?", "What do I need to say in this letter to my bank manager?", "I need to get that proof printed for marking up" and things of that nature. To them, a computer is just a tool; you wouldn't get out your woodworking kit without something to build in mind, so why start up a computer without a job in mind?

Cheating: Not just for Microsoft anymore

Posted Oct 7, 2008 12:59 UTC (Tue) by Janne (guest, #40891) [Link]

"why does she have to wait 45 seconds for the OS to boot?"

She doesn't. I mean, you can apparently boot Linux in 5 seconds ;).

"In short, why is using a computer with a 1.83GHz Core 2 Duo and 4GB of RAM
full of delays, when using an IPTV set top box with typically 100MHz CPU
and 32MB RAM is not?"

Well, that set-top box is designed to do one thing, and it's designed to do
it on one hardware-configuration. So they can optimize it like crazy. Those
do not apple to Linux.

that said, my DVR takes about 5-10 seconds to boot. My DVD-player takes few
seconds as well. My router takes about 10 seconds to become reachable.

"If you allow delayed service startup to not count, the danger is that
you'll discount services that matter to users."

But the thing is that we already have slow as hell boots, even with delayed
services. Like I said, my laptop running OpenSUSE takes ages to boot, and
when I DO get to the desktop, it's STILL not connected to the network! So
the difference between this fast booting and my OpenSUSE is that Arjans
system takes 5 seconds to boot, after which it takes few more seconds to
connect to the network, whereas my laptop takes 45-50 seconds to boot,
after which it takes few more seconds for it to connect to the network.

In other words: it takes just as long for the two systems to connect to the
network. The difference is that the things that happen before that net-
connection take 45-50 seconds on my laptop, whereas on Arjans EEE it only
takes 5 seconds.

And how would you connect to the WiFi befire getting to the desktop? I
mean, you might need to enter passwords and the like? Should the computer
stop booting and prompt you for your WPA-passowrd? No. It should get you to
the desktop and in to an usable state, and prompt you for any needed WiFi-
passwords as needed.

"Indeed, you're already trying to handwave away an important service for
some use cases as "takes too long, and anyway users can wait"; this is
exactly why someone doing the challenge must set a defined state in which
boot is finished. Given the defined state, I can now look at it, compare it
to my use cases, and say "yes, that's good enough", or "no, I need to work
out how to fit WiFi startup into that 5 seconds"."

But Wifi is not part of what we usually think of when we talk about
"booting". And like I said: I see no difference between this 5-seconds boot
when compared to normal booting, if we think of Wifi alone. In either case,
WiFi is disconnected at the end of the boot.

"Plus, my experience of normal users is very different to yours - they
don't have computers waiting and switched on, they don't start the computer
up without a task in mind, they start the computer thinking "Do I have any
e-mail waiting?""

Sure. But let's compare two scenarios:

Normal distro:

User turns the computer on. It boots for about 45 seconds, and the user
logs in. After he gets to the desktop, he needs to wait for few seconds for
the network to become usable. Then he can check his mail

Arjans EEE:

User turns on the computer. It boots in five seconds. User needs to wait
for few more seconds for network to become usable. Then he can check his
email.

How is that normal distro handling networking better than the EEE is? It's
not online either, at the end of the boot.

removing WiFi from the equation we can focus on the subject at hand:
booting. WiFi relaies on other things that are totally outside the scope of
this project.