VerbAtim

Pintos- implementing the mlfqs scheduler

noreply@blogger.com (Ankit) — Mon, 09 Apr 2012 17:30:00 +0000

Hi, Its been a while since my last post on pintos, as I have been quite busy at work. As promised in the last post, here is the link to my pintos repository : https://github.com/sup3rcod3r/pintos. You can watch it to keep up with the developments.
A quick way to clean and compile any code changes is to run
$make clean && make check
from the project/build folder. This compiles the kernel and starts running all the tests.

In the next exercise, I skipped the priority donation part, and jumped on to implementing the mlfqs scheduler. It was quite a fun exercise, getting to learn about fixed-point arithmetic, and its use in the pintos kernel, where float numbers aren't supported. An important point to remember is that you have to consider the idle thread while calculating load-avg and recent-cpu values. Since it doesn't contribute to these values, it is good to check for it in the get functions, and return if true. After I got this bit right, nearly all of the scheduler tests passed.
Output as of now :

pass tests/threads/alarm-single
pass tests/threads/alarm-multiple
FAIL tests/threads/alarm-simultaneous
pass tests/threads/alarm-priority
pass tests/threads/alarm-zero
pass tests/threads/alarm-negative
FAIL tests/threads/priority-change
FAIL tests/threads/priority-donate-one
FAIL tests/threads/priority-donate-multiple
FAIL tests/threads/priority-donate-multiple2
FAIL tests/threads/priority-donate-nest
FAIL tests/threads/priority-donate-sema
FAIL tests/threads/priority-donate-lower
FAIL tests/threads/priority-fifo
FAIL tests/threads/priority-preempt
FAIL tests/threads/priority-sema
FAIL tests/threads/priority-condvar
FAIL tests/threads/priority-donate-chain
pass tests/threads/mlfqs-load-1
pass tests/threads/mlfqs-load-60
pass tests/threads/mlfqs-load-avg
pass tests/threads/mlfqs-recent-1
pass tests/threads/mlfqs-fair-2
pass tests/threads/mlfqs-fair-20
pass tests/threads/mlfqs-nice-2
FAIL tests/threads/mlfqs-nice-10
FAIL tests/threads/mlfqs-block

Follow the requirements closely, as they contain most of the clues to finishing the exercise.

pintos init

noreply@blogger.com (Ankit) — Fri, 02 Mar 2012 15:26:00 +0000

The following post is for those looking to setup a working environment to start work on pintos project. I am documenting ways to overcome some difficulties at start, as my hard-disk is reporting "crash imminent" and I may need to do this again later.

Started working on a new hobby project pintos last weekend.
The intro can be found here: http://www.scs.stanford.edu/10wi-cs140/pintos/pintos.html.
I started with setting up the environment by following steps given here: http://www.scs.stanford.edu/10wi-cs140/pintos/pintos_12.html#SEC166
While I was breezing past the first 3 points (bochs installed, setting path to add gdbmacros,src/utils), I hung up on the 4th i.e. Compile the remaining Pintos utilities by typing make in src/utils. The problem when I invoked make is that make file generates commands like
$gcc -lm squish-pty.c
which resulted into error with my version of gcc, as -lm . So, had to ignore makefile, and ran those commands individually:
$gcc squish-pty.c -o squish-pty -lm
then, copied each generated executable into PATH directory.

A second problem that was lurking was, bochs didn't install correctly and would crash, when running the pintos command. Downloading a prepatched version of bochs from http://cit.dixie.edu/cs/3400/pintos-install.php, helped.

In the next post, I will give the git url for this project, and provide new ideas and materials to learn from to complete the project.

noreply@blogger.com (Ankit) — Thu, 06 Jan 2011 11:24:00 +0000

FB

noreply@blogger.com (Ankit) — Sun, 03 Oct 2010 18:05:00 +0000

a few questions, some clicks and a couple of seconds later, I became another pround owner of an fb account.
Opening my home page, I thought "cool, this sns is far more vibrant and active than orkut!", and why not, most of my friends abandoned orkut for fb, when it was making news about stealing users' information.
as of now, it seems ppl do react to others' status and pics on fb, which used to happen centuries ago on orkut too!

Confessions of an amateur photographer

noreply@blogger.com (Ankit) — Sat, 14 Aug 2010 18:19:00 +0000

Ok, so here go my first few attempts at photography.

This is one of the tricks I have been wanting to do for years :) . It is easy to achieve in an SLR by simply increasing the aperture time. But in my cam (Nikon 120), I achieved it by setting the camera for night mode photography. The aperture does open for a longer duration, however precise control over it is something I still miss.

I used the Digital Macro mode available in my camera for this image, which thus renders an enlarged and clear image of the center drop while keeping the background out of focus.
The Macro mode opens a whole new world of photography subjects to be explored, some of which can be seen below.

Rose thorns. Notice the joints of the thorns with the stem.

This is one of my favorites. The subject was a dead bug, I found in the garden. Notice its broken eye and sticky hair on its limbs and thorax.

A group of ants. Some of their feet aren't clearly visible because they were moving.

This pic was taken after the rain.
The water drops add freshness to the image and the flower bud gives composure and balance to the colors blah blah blah.
The conclusion is that it is a good image and is currently my wallpaper :)

Nature photography:

You can see a beak and an eye of a bird poking out of its nest. I don't know which type of bird it is, but it worked very hard to build itself a nice, green nest on one of the mango trees.

A beautiful rose.
Nothing to say here.

A nice silhouette.
A crow perched on a transmission line.

reminds me of a wallpaper that used to come with Windows-98.
But this one is more vibrant and is shot by me!

Icon of CS1.6. You can easily see each pixel on the laptop screen showing different colours by varying the RGB values.

So, these were some of my pics from my still new camera. Hope u like them.

The summer of 2010

noreply@blogger.com (Ankit) — Fri, 06 Aug 2010 19:54:00 +0000

Exactly 3 months ago, I gave my BTP presentation; and thus ended a 4 year journey called college.

Never had I enjoyed, procrastinated, fooled around, partied, bunked, slept (in short "lived") as much as in these last four years. And as the realization of its end dawned upon, a nostalgic feeling started sinking in.

The next week was all about no dues forms, assi ghat, godowlia and lanka :)

I reached home on May 15th with a hard-disk full of tv series and some games.

Now as you all know, the first few days at home are like time spent in heaven. And then comes the boredom :(

So, I started with Lost, smallville, himym and justice league (the series aired on CN). Took a month to complete. I also had to go to a family wedding by the end of the month for a week. Spent some quality time there.

So, the first month was spent easy.

Oh, FYI my joining is on 16th Aug. So, I had 3 months this summer to spend at home.

Most of the material on my hard disk was watched and the FIFA worldcup was going to start. I started reading a bit about football, but let's face it; the football fever subsided faster than it had attacked me.

I never followed football before, couldn't stay up late at night and had problem remembering most of the players' names.

Meanwhile I had applied for a BSNL broadband connection, before the worldcup.

The telephone was installed 2 weeks after the worldcup :( and the modem took another full week :((

By then, I started getting newsletter and emails from the company, giving light homework and recommending books to study. I didn't download any book.

I got my hands on a cool DIY book, which had instructions for projects I had been wanting to do for months, like FM transmitter bug, remote control of laptop by bluetooth etc...

I started looking for electronic components in Dhanbad but I couldn't find most of my requirements.

So from the small inventory of electronic components I did manage to get, I built myself a cool astable-multivibrator, a pic of which I am shamelessly pasting here. ( this ugly no-use circuit cost me 200 bucks)

home made circuit.

Meanwhile, I was also getting interested in bash programming, java midlets, android platform and website designing. I also read some tutorials and made mobile apps. Now I was determined to buy an android phone some day. Sometimes you have a "this is gonna be BIG" feeling and want to go with the flow. I spent quite some time researching android phones currently available in the market.
You can get an idea from here. I rounded up on samsung-spica, but it seems samsung has stopped its production. Can't find it anywhere in Dhanbad as of now. Will search for it in mumbai :)
As of now, I received a cool gift from my parents, a brand new Canon Ixus 120IS :)

google for its specs, nice cam btw. I am currently busy fiddling with its features and settings.

I will be posting photos taken from my new cam in a few days. So stay tuned.

KY'10

noreply@blogger.com (Ankit) — Sun, 24 Jan 2010 16:30:00 +0000

Participated in the T-shirt designing contest Toolika during the cultural fest of IT-BHU Kashiyatra. Looks cool :).

My own media player!!!

noreply@blogger.com (Ankit) — Thu, 21 Jan 2010 13:20:00 +0000

This is my first post of the new year. And I am posting a link to the first app. I made this year

This is the media player I had been working on for quite some time (and which kept me away from blogging :) )
Complete with playlist feature and capability of playing .flv and .mp3 files, the release is a .air installer. For running a .air application, you will require the Adobe Integrated Runtime.
Here is a screenshot of the player. Hope you will like it :)

Mobile phone prices in India

noreply@blogger.com (Ankit) — Thu, 17 Dec 2009 16:00:00 +0000

Mobile phone prices in India

My first chrome extension!!

noreply@blogger.com (Ankit) — Tue, 15 Dec 2009 18:26:00 +0000

Here is a cool new chrome extension that shows the first five feeds of my blog in rotation. Try it!
here is a screenshot->

First Job!!!

noreply@blogger.com (Ankit) — Wed, 09 Dec 2009 08:11:00 +0000

Got a job in CTS along with 158 others from IT-BHU. Feels great!!!

New Widget!!!

noreply@blogger.com (Ankit) — Tue, 08 Dec 2009 18:01:00 +0000

Added the new feed subscription widget, so you readers can keep up with my blogs. Enjoy!

when was the last time you did something for the first time?

noreply@blogger.com (Ankit) — Mon, 07 Dec 2009 15:54:00 +0000

today, I shaved off my moustache for the first time!

Flexing my muscles

noreply@blogger.com (Ankit) — Mon, 07 Dec 2009 07:10:00 +0000

Having finished with the CAT yesterday, I turned to the one task I had in my mind for the last couple of days. I had joined the Flex Developers community of our college and was wondering what the fuss was all about.
I downloaded Adobe Flex yesterday, and started fiddling with the sample codes. At first, what seemed to be like a "dreamweaver" like IDE from Adobe, gradually started unfolding its plethora of controls. As I started with the programming(or rather designing), I realised, I could even make a light browser in a couple of lines of code. Then I decided, that maybe, this browser could draw people to my blog :) . So, I removed all the controls from this browser and distributed the empty container as an installer whose raison d'etre would be to open my blog.
Soon I will have my own website based entirely on flex. I hope. :).

World Wars

noreply@blogger.com (Ankit) — Sun, 08 Nov 2009 20:05:00 +0000

We all know about the world wars and the way they influenced the future of mankind. But nothing can be compared to the one which is happening right now,even as I write this blog.
Traditionally wars were between nations for control of colonies and their natural resources. Today, in the information age, wars are fought between companies, software giants and minnows alike. Though the motive has remained the same, but the resource is knowledge.
Google-search, which was started merely 12 years ago, has now the most used search engine on the web. In response, microsoft launched its own version of search engine "Bing". Wolfram-Alpha, though not fully developed, brings a cool new dimension to "searching".It basically associates keywords with numbers and vice-versa to present the result in the form of graphs, charts, facts and more! Various other search sites such as ask,yahoo,lycos are also used, but rarely!
In July, this year, Microsoft and Yahoo entered in a deal according to which Microsoft would power Yahoo! search while Yahoo! would become the exclusive worldwide relationship sales force for both companies’ premium search advertisers. Definitely, the move was made to increase their share in global search engine usage against that of Google.
Information on-the-go is available on smartphones, and the biggest contenders in this arena are Nokia, Motorola and Apple. Recently, the Finnish mobile giant Nokia sued Apple over copyright infringement. There are more battles to come on the global tech arena like Motorola Droid(with Google Android OS) vs Apple Iphone, Windows7 vs Karmik Koala(the 9.10 release of Ubuntu, described as the official alternative to Windows), Google Wave and many more, a harbinger of good things to come. And I am keeping my eyes open :)

NASA Images

noreply@blogger.com (Ankit) — Sat, 08 Aug 2009 05:11:00 +0000

Added NASA image of the day widget, to give an "Out of the World" feel to my blog...

Euphoria

noreply@blogger.com (Ankit) — Fri, 07 Aug 2009 18:48:00 +0000

close, turn-off, shut-down the box
wanna come-out ,speak ,shout like a fox
Gripped by loneliness, hebetude, claustrophobia?
No, dont hide, come in the light, Euphoria!!!

source code of quick-sort

noreply@blogger.com (Ankit) — Fri, 07 Aug 2009 17:14:00 +0000

Two days after starting to write the code for quick sort, from scratch, I was finally able to make it error free. The algorithm is elegant but error prone and to make matters worse (from the point of view of program readability) recursion is an integral part of the code.
I searched heavily for the code but couldn't find any of them written in C++, and clean enough.
So I decided to blog it down, for my own future references and above all, for the whole coding community.

#include "iostream"
#define max 9
using namespace std;

void display(int* a)
{
for(int i=0; i< max; i++)
printf("%d",a[i]);
printf("\n");

}

void swap(int& x,int& y)
{
int temp;
temp = x;
x = y;
y = temp;
}

int partition(int* a,int beg,int end)
{
int left = beg, right=end, piv = *(a+beg);

while(left {
while((a[left]<=piv)&&(left left++;
while((a[right]>=piv)&&(right>beg))
right--;
if(left swap(a[left],a[right]);
}
a[beg] = a[right];
a[right] = piv;
return(right);
}

void quick(int* a,int beg,int end)
{

if (beg>=end) return;

int pos = partition(a,beg,end);
cout< quick(a,beg,pos-1);
quick(a,pos+1,end);
}

int main()
{
int arr[] = {1,5,2,7,3,4,6,0,9};
display(arr);

quick(arr,0,max-1);
printf("After Quick Sorting:");
display(arr);

system ("pause");
return 0;

}
The program was written in Dev C++ version 4.9.9.2
Compiler used- g++

CS Source

noreply@blogger.com (Ankit) — Mon, 20 Jul 2009 18:51:00 +0000

Tonight I was messaging my fellow players to join the CS Source Server, when accidentally words began to appear in some sort of phonetic order.....a poem. Have a look...

we didn't start the fire ,
but we did retire
for, the bomb was not ours
they conspired against us
They said, they were the "messengers of peace"
We knew, they were mere mercineries for hire.
- Ankit (T)
JOIN CS Source only on 10.8.31.96 tonight.