Environmentally responsible coding

How many of you have considered the environmental impact of the code you write, or code you use on a daily basis?

Pulling a number from somewhere, a typical PC might draw 200 watts when doing something intensive. At the wall, the inefficiency of the PSU will cause the actual power to be somewhat higher, let's say 300 watts.

Let's consider some heavily used code. For instance, the JPEG decoder present in all web browsers.

Suppose there are half a billion active Internet users. Let's also suppose that each user uses the web, and views an average of 5000 JPEGs per day (a typical page might have a hundred or more images on it, so this is probably an underestimate). So, the JPEG decoder executes about 2.5 trillion times per day.

Suppose it takes on average, 0.02 seconds to decode a JPEG. Remember, some JPEGs are large, some are small.

Starting from these assumptions, what is the energy impact of a 10% improvement in efficiency of the JPEG decoder?

2.5e12 * 300 watts * 0.002 seconds = 1500 gigajoules.

That's the equivalent of burning about 12000 gallons of gasoline every day. In a year, that's 4.4 million gallons.

Imagine having the ability to spend a few hours optimizing something, and the end result is that 4.4 million fewer gallons of gas are burned each year?

Something to think about.

Well, I'm pretty sure I'm not always consuming more energy because I'm using a JPEG decoder while my computer is turned on. I don't think that's how the PSU works in our computers, is it? (honest question. I trully don't know). Besides a gain in performance will most of the time mean an increased expense in processor usage... which would also translate to power consumption, no?

Perhaps efficiency would be a better goal. More time to process if needed be, but at a less overall energy consumption cost.

But looking at those numbers, and assuming a worldwide concern towards environmental impact of energy consumption, imagine the gain if instead of looking at performance we all turned off our computers when we weren't using them. Or, perhaps even more significant to the point at hand, if we curbed our use of JPEGs/Flash/Client-side scripting/etc... in websites.

Performance for the benefit of the environment seems like arguing for animal fur coats because synthetic fur coats take longer to biodegrade.

Yes, this is one reason why C is ultimately better than C++ even tho it requires more effort on the part of the programmer. :p

I pretty sure it is all trivialized by the amount of "real driving" (read: real driving) that most computer users/owners/programmers do during their normal daily activities.

I can totally see some absurd future greenwash marketing whereby browser X is sold as more environmentally friendly.

Quote:

---

Originally Posted by Mario F.

Well, I'm pretty sure I'm not always consuming more energy because I'm using a JPEG decoder while my computer is turned on. I don't think that's how the PSU works in our computers, is it? (honest question. I trully don't know). Besides a gain in performance will most of the time mean an increased expense in processor usage... which would also translate to power consumption, no?

---

I've actually measured it with a wattmeter at the wall. There's a significant difference between an idle CPU and a maxed-out CPU.

As far as performance gain actually taking MORE power, it depends how it's implemented in the first place. It's easy to max out a CPU by doing unnecessary work. Simply removing the unnecessary work doesn't reduce the power, but it does reduce the amount of time that power is required for.

Quote:

---

Perhaps efficiency would be a better goal. More time to process if needed be, but at a less overall energy consumption cost.

---

That's strictly more accurate, but it requires knowledge of how much power the various parts of a CPU consume. For instance, if you know that the SSE3 unit takes five times the power as standard floating point, you might choose floating point even if it makes the code run three times slower.

Quote:

---

But looking at those numbers, and assuming a worldwide concern towards environmental impact of energy consumption, imagine the gain if instead of looking at performance we all turned off our computers when we weren't using them. Or, perhaps even more significant to the point at hand, if we curbed our use of JPEGs/Flash/Client-side scripting/etc... in websites.

---

You're right of course, but the reality is you simply can't MAKE people do it. But you can tweak a piece of code that's used worldwide, and eventually everybody will be running it, through no deliberate action of their own. You made the difference all by yourself instead of needing to convince a billion people to turn off their computers.

Quote:

---

Originally Posted by Mario F.

Client-side scripting

---

I am guessing that moving the load server side will reduce the "carbon footprint" in your house, but result in an overall increase because of the necessary server upgrades. Maybe you can then sell your carbon credits to the sites you visit, so everybody can think* something has been accomplished.

If you think that people will go for a "less is more web" then maybe you also believe they will go for a "less is more" transit style, or "less is more" packaging at the supermarket.

The last two have been beyond absolute total and complete failures for decades, as would this. People do more gas gussling and consume more pure garbage, per capita, now, than ever before. So again, the only real "accomplishment" to attain would be an advertising gimmick.

* to use the word loosely

I don't believe in anything. I was purposely exposing the irony of the situation. I agree entirely with you two that is just not how the world eventually works. But I felt the need to remember one less JPEG in a 10 JPEGs webpage, will have a greater impact than a 10% increase in the decoder efficiency. The irony resides in the fact that's just not a good solution anymore.

I think Javascript and Flash advertisements are the predominant causes of high CPU usage.

I always browse with JS turned off, which makes websites load faster(and reduces the risk of malicious JS embedded in the webpage). I only turn JS on if particular sites require it, like for banking.

I remember reading in the Linux kernel changelogs at some point that they changed the architecture a little bit so that a wakeup timer no longer fired every second. After this change you could actually let your computer sit there while it was running and get many fewer CPU wakeups per second (theoretically zero, but most other devices wake it up every so often as well). I thought that was a great idea at the time, because if you use powertop for a while you start to realize how much power you save by keeping the CPU in standby mode as long as you possibly can . . . .

I imagine that sort of change had a measurable impact on power consumption (at least for Linux users), because it's in the kernel and it applies all of the time. Anyway, it was just what came to mind when I read this thread.

[I should mention that I probably got half the terms there mixed up, I really don't know very much about the subject . . . .]

Never thought about it. Probably won't a few seconds after reading this either.

Most oil drums: 55 US gallons
Last estimate of leak in the Gulf: ~5000 barrels a minute or 275,000 gallons per minute, 16,500,000 per hour, 396,000,000 per day.

Total required for 1 hour of use for half a billion users with usage of 12,000 gallons per day: 500 gallons per hour
Percent of power required out of total in one hour given a flow rate of 275,000 gallons per minute (16,500,000 per hour) and usage of 500 per hour for half a billion users: 500 / 16,500,000 = 3.030~030 * e^-5%.

So that one leak in the Gulf produces enough oil in one hour to power half a billion users with a usage of 12,000 gallons per day for 33,000 (396,000,000 / 12,000) days or 90.14 years.

And besides electrical power isn't normally produced from oil, it is produced from coal and/or nuclear and/or water.

Microsoft should really do something for the environment.

Quote:

---

Originally Posted by Brafil

Microsoft should really do something for the environment.

---

So should the makers of Hostess potato chips, etc, but I think the most you will learn about "social responsibility" in business school is how to hire a PR firm to clean your exposure/profile while minimizing any other possible expenditure.

Capitalist enterprise, by it's very nature, is simply not capable of "doing something for the environment". If this were not the case, it would have happened by now, but it has not and it won't be in the future, either.

Ok a little update on the numbers. Recent reports say the leak is around 4 million gallons. That does not equate to the aforementioned 5000 barrels a minute. So once again the first reports coming out were completely exaggerated and the more recent reports are still exaggerated but getting closer to the actual number...if that is even possible given the conditions.

Quote:

---

Originally Posted by MK27

So should the makers of Hostess potato chips, etc, but I think the most you will learn about "social responsibility" in business school is how to hire a PR firm to clean your exposure/profile while minimizing any other possible expenditure.

---

Part of the point I'm making is because of the nature of software -- created once and then deployed without bound -- a single developer can make a large difference. Even if that difference is insignificant on a global energy balance, the rate of return per person involved is huge.

How much impact can you make by selling your car and riding a bike? How much by installing energy efficient appliances? By turning things off and unplugging them when not in use? Can you make 4.4 million gallons difference?

I'm not saying that "green" programming will save the world.

Quote:

---

Originally Posted by brewbuck

Part of the point I'm making is because of the nature of software -- created once and then deployed without bound -- a single developer can make a large difference.

---

Sure, and you could write CLI interfaces more too, that would make a way more huge difference in terms of resource usage. But let's be realistic -- the environment is not worth people having to use the command line! :p

Course not. That would require many hours of additional computer courses for most of the users, which means more fuel is wasted for transport.

But maybe... Microsoft could make a light windows system with nice graphics (XP-Style) and low system requirements...

I think brewbuck's point is about doing something on those areas where one can intervene and that have a high impact. Assuming the numbers are right, I can surely see his point. And it's an interesting one. Any skepticism won't remove the fact it's a valid point.

Being fatalist about it, or comparing to other areas where we could do a higher impact, will do nothing. The whole point of Action is to do something, not sit around looking at what hasn't been done.

Yet, I do agree that to some extent that hoping software developers will optimize their algorithms is akin to hoping the web will start using less images. It's just not going to happen. Surely there's a desire to optimize code. But this ends when the code performs as required. And that is also affected by other external factors, like an increase in broadband or the average processor clock. Going beyond that requirement is often seen as unnecessary and even risky, considering the possibility of introducing bugs or making the code harder to maintain.

So we need to match our green conscious with what we have been taught during our academic studies and throughout our careers. They aren't just that much compatible. Green in this context, goes pretty much against everything we have bee told; Do not over-optimize, don't fix what is working, do not add unnecessary complexity, keep your code readable.

Quote:

---

Originally Posted by Brafil

But maybe... Microsoft could make a light windows system with nice graphics (XP-Style) and low system requirements...

---

The technology behind current operating systems concerning energy consumption is pretty much transversal to all of them. Pointing a finger at Microsoft won't help, when you then have to point a finger at Apple, and a large part of the Linux community responsible for projects like Gnome or KDE and distributions like RedHat, SUSE or Ubuntu.

Ultimately you would need to point the finger at yourself for your use of the computer which is largely composed of moments doing nothing, or nothing deemed meaningful. Turn your argument on its side and you will be facing the same kind of responsibility concerning energy consumption in your house. In the end, there's so much software providers can do. The real use of the energy is what matters. And that is happening right now in front of you and as you read this.

So stop the Microsoft bantering. Makes you look like the rest of the useless bunch out there screaming for a greener planet, but refusing to let go of their comfort, their wool and cotton clothes, and their computers.

I don't blame Microsoft, that was just a nice kick in the side.

I know that there are far more important things about environmental protection - for example old cars using tons of fuel (I use trams and busses) and millions of trees being knocked down for... Soy beans? For chicken. That's why I don't eat those types of things...

at least not often... I prefer organic food...

Quote:

---

Originally Posted by Brafil

I know that there are far more important things about environmental protection - for example old cars using tons of fuel (I use trams and busses)

---

Using the same old car for twenty years, no matter how poor the fuel economy is, will always be more friendly on the environment than changing cars three times in the same period.
Producing a brand new car is a CO2 heavy task, and especially the batteries for electric and hybrid cars are really bad.
If you wan't to spare the environment, keep your car for as long as possible.

I don't speak about changing your car every three years - I think that keeping a car from the 1950s, including maintenance of the car, is worse than having a decent one. Of course you should use a car as long as possible, but this doesn't apply for the cars I wanted to mention, which may even need lead in their fuel.

If companies try to recycle cars, a part of this CO2-waste is prevented as far as I know.

Quote:

---

Originally Posted by Brafil

Course not. That would require many hours of additional computer courses for most of the users, which means more fuel is wasted for transport.

---

Oh malarky. Using a command line app just requires you to remember words and patterns, and exercising your memory does not require computer training. Anyone who can talk can remember words and patterns.

Anyway, I didn't mean get rid of the GUI desktop. You might have to add some functionality to the basic windows terminal, which is to say, improve it, otherwise of course no one will want to write CLI's for the MS platform. People have been misled into believing that a GUI is "by definition" easier to use than the command line, and this is often not true. They certainly tend to use way way fewer system resources, and are less persistent.

Well, my mum would probably go crazy if she saw even a tiny edge of the command line and would refuse to do anything. I think there are many people like this. Try to tell her how to cd. And a big bonus of Microsoft (and of Apple) was that there was no need for a terminal anymore.

Quote:

---

Originally Posted by Brafil

Well, my mum would probably go crazy if she saw even a tiny edge of the command line and would refuse to do anything.

---

This is what I meant by "People have been misled into believing...". I think the irony is that if your mom is anywhere close to my mom's generation and worked in an office in the 1980's, they used all kinds of terminal interfaces. Meaning there was often some typing and syntax (such as ctrl key combos) to remember. I still see them in a lot of supermarkets and with warehouse inventory systems. So it is only an alien thing to people <35.

Well, my mom apparently never worked with such kinds of things.

Quote:

---

Originally Posted by Mario F.

Being fatalist about it, or comparing to other areas where we could do a higher impact, will do nothing. The whole point of Action is to do something, not sit around looking at what hasn't been done.

---

I wasn't being a fatalist so much as raising the issue of the potential for grotesque self-congratulatory behaviour here. This is why it is important to understand that capitalist enterprise alone CANNOT do much good for the environment, because that is something that REQUIRES SPENDING -- there is no potential for personal or institutional profit, except in so far as one might procure government contracts, heh-heh.

Throwing shot glasses of water on a towering inferno does not cut the mustard. If (programmer or no) you cannot perceive ways of helping to effect much more drastic changes in behaviour than this, then don't kid yourself -- this is simply a feel good exercise.

Quote:

---

I don't speak about changing your car every three years - I think that keeping a car from the 1950s, including maintenance of the car, is worse than having a decent one. Of course you should use a car as long as possible, but this doesn't apply for the cars I wanted to mention, which may even need lead in their fuel.

---

Actually I'll trade my car when and if it dies or when I feel like trading it. I'll use a car as long as it is economically viable for me to do so and not a minute longer. Since I'm a performance car kinda guy I rarely buy a car for MPG plus I realize the MPG numbers are way off anyways.
The worst thing you can do to a fuel-injected car is putter around in it and clog up all the injectors. You will spend more cleaning the fuel system and cause more pollution b/c the injectors will get clogged forcing the computer to ask for more and more fuel. Honestly modern cars don't cause that much pollution when properly maintained.