Thursday, May 9, 2019

Hosting a RIPE ATLAS Probe in Atlanta

I used RIPE Atlas for my Internet measurements in my IFIP Networking 2018 paper (NetUber: A cloud-assisted overlay network as an alternative connectivity provider) and consequently my thesis. I consumed the RIPE Atlas credits from my co-author for those experiments. Afterward, I requested RIPE to send me a probe, and now I have received it! I have connected it to my home router. My probe is currently connected to the RIPE Atlas network and started receiving traffic. I am happy to contribute back to the Internet measurements community!

Friday, April 19, 2019

Thermald and MCE error

I randomly kept getting the below errors in my Centos laptop. I installed thermald. It seems the error is fixed for now. Let's see. :)

Message from syslogd@llovizna-lenovo at Apr 17 14:29:02 ...
 kernel:mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 5: ee0000000040110a

Message from syslogd@llovizna-lenovo at Apr 17 14:29:02 ...
 kernel:mce: [Hardware Error]: TSC 0 ADDR fef81fc0 MISC 78a0000086

Message from syslogd@llovizna-lenovo at Apr 17 14:29:02 ...
 kernel:mce: [Hardware Error]: PROCESSOR 0:40651 TIME 1555525734 SOCKET 0 APIC 0 microcode 24

Message from syslogd@llovizna-lenovo at Apr 17 14:29:02 ...
 kernel:mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 6: ee0000000040110a

Message from syslogd@llovizna-lenovo at Apr 17 14:29:02 ...
 kernel:mce: [Hardware Error]: TSC 0 ADDR fef82100 MISC 78a0000086

Message from syslogd@llovizna-lenovo at Apr 17 14:29:02 ...
 kernel:mce: [Hardware Error]: PROCESSOR 0:40651 TIME 1555525734 SOCKET 0 APIC 0 microcode 24

$  dmesg | grep -i 'mce:'
[    0.023131] mce: CPU supports 7 MCE banks
[    1.037974] mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 6: ae0000000040110a
[    1.038009] mce: [Hardware Error]: TSC 0 ADDR fef87380 MISC 278a0000086
[    1.038033] mce: [Hardware Error]: PROCESSOR 0:40651 TIME 1555486489 SOCKET 0 APIC 0 microcode 24
[  300.672620] mce: [Hardware Error]: Machine check events logged
[24841.300647] mce: [Hardware Error]: Machine check events logged
[24841.300730] mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 5: ee0000000040110a
[24841.300735] mce: [Hardware Error]: TSC 0 ADDR fef81fc0 MISC 78a0000086
[24841.300739] mce: [Hardware Error]: PROCESSOR 0:40651 TIME 1555525734 SOCKET 0 APIC 0 microcode 24
[24841.300743] mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 6: ee0000000040110a
[24841.300747] mce: [Hardware Error]: TSC 0 ADDR fef82100 MISC 78a0000086
[24841.300750] mce: [Hardware Error]: PROCESSOR 0:40651 TIME 1555525734 SOCKET 0 APIC 0 microcode 24

Sunday, April 14, 2019

My EMDC Erasmus Mundus Journey

KTH Welcome Reception at Stockholm City Hall, 2013
7 years ago in 2012 August, I arrived in Lisbon for my Erasmus Mundus masters program, European Master in Distributed Computing (EMDC). My mobility was, IST (Lisboa, Portugal) -> KTH (Stockholm, Sweden). My first academic year should be in Portugal and the third semester (first half of the second academic year) should be in Sweden. The final semester is the thesis, and it was proposed that it should be in KTH, Sweden, although it was not set in stone, unlike the first 3 semesters.

KTH Main Campus in Summer
Initially, my grant was in a waiting list, and I was careful with the money. But I was approved for the full scholarship, Category "A" soon after. This eliminated my worry about money. I had planned to spend just one year in Portugal and the second year in Sweden. However, I decided to come back to IST for my final semester for my master thesis.

The first semester was interesting. Everything was new. We had a group of international students doing our Erasmus Mundus program. We all were always together. We also had other international students from various other mobility programs.

KTH Main Campus in Autumn
Portugal was my 4th country to visit. Lisbon was my second city in Europe. My first trip was in 2010 to Paris. Of course, at first, Lisbon felt underwhelming compared to my expectations based on Paris. However, it became a positive experience quickly. We had 2 out of the 4 courses of the first semester in Taguspark. We would take the IST shuttle in the morning to commute to Taguspark campus from the Alameda campus. My apartment was in a walking distance to the Alameda campus where we had most of the lectures. We often had meals in the canteen - the Taguspark canteen was much better than the ones in Alameda. We also had a winter event in Nuria, Spain in the snowy mountains. We enjoyed the snow and the -11℃.

View of the Langholmen island, Stockholm
Our move to Stockholm was smooth. We had more students in KTH/Sweden in our group compared to IST/Portugal, as all the students of EMDC had to spend one semester in KTH. While we spent our first year in IST, Portugal, the other half of us had spent their time in UPC, Barcelona, Spain. Stockholm was fun. It had lots of lakes and forests. Its metro stations were beautiful. It also had a popular story involving a discontinued metro station, Kymlinge, and an old Silverpilen (silver arrow), the Ghost Train. Summer was long and comfortable. Winter was depressingly dark. But inside our apartment, it was warm enough. Unlike Lisboa, Stockholm had a good central heating.

EMDC Summer Event in Fejan
For the final semester, I decided to come back to IST for the master thesis. Everyone else either stayed at KTH or went on to different companies or research labs. So I was back to INESC-ID Lisboa. But my experience was entirely different from 2012 and 2013 when I had a big group. Anyway, I successfully completed EMDC, with a score of 18/20 for the master thesis, with 2 publications (at MASCOTS and UCC). I also worked at UniPlaces as a part-time software engineer by the end of the 3rd semester to early 4th semester.

Gamla Stan
Masters in Europe, specifically the Erasmus Mundus mobility programs, are very exciting. I decided to continue my higher education in Europe with Erasmus Mundus. I applied for EMJD-DC (Erasmus Mundus Joint Doctorate in Distributed Computing) and got selected with the category A scholarship. Finally, my EMDC came to a successful end.

We also had 2 graduation ceremonies. One for KTH at the Stockholm city hall where they usually present the Nobel awards! We also had our welcome reception in the city hall when we arrived in Stockholm. Most of us had a reunion there meeting our friends after a long time during the KTH graduation ceremony. We also had a graduation ceremony at IST. But unfortunately, it was only me who was attending. Luckily, I was staying in Lisboa for my EMJD-DC at that time. Overall, EMDC left me with very happy memories and no regrets! Given a chance, I would not do anything different. :)

Thursday, April 11, 2019

Memories of Portugal

When Portugal hosted the Eurovision 2018
Memories of Portugal is a series of blog posts, attempting to recall my vivid memories of Portugal for the past several years. I have been writing these posts for quite some time at intervals. It has been after all a long journey. When I look back, even the boring routine stuff I did in Portugal makes exciting memories.

My 6-year long stay in Portugal (2012 August - 2018 June) had 4 segments, with some interval between each segment as I had to migrate to another country in between due to the Erasmus Mundus mobility requirements. Given below are 4 episodes of my life in Portugal, each describing one such segment of my stay. My trip to Portugal for my Ph.D. defense would qualify as the Episode 5, and I have no idea when will I travel again after that to write an Episode 6. But I have a feeling we will, sometime in the far future.

Episode 1: Friendships and Goodbyes

Episode 2: Welcome back Home  

Wednesday, April 10, 2019

Ep 1: Friendships and Goodbyes [Memories of Portugal]

This post is part of a series on my life in Lisboa.


1.1: Moving In 
2012 August
Getting used to life abroad
When I arrived at Lisboa airport on the 23rd August 2012, I did not know that Portugal and specifically Lisboa would become the one-word summary of my 2010s. I also did not realize Lisboa airport will become my most frequented airport, even more than the Colombo airport, the airport of my home country. Within the years, Lisboa airport had also become a second home to me - making me feel relaxed and comfortable while I wait for my next flight.

View from our apartment
My landlord was waiting for me at the airport with my name on his iPad. He showed me around the neighborhood - the supermarkets, my university, bank, university admissions office, and other closeby places of interest such as Campo Pequeno. Shopping in Lisboa - both for groceries and other fun shopping - was quite fun. It has many shopping malls and supermarket chains. There were 3 major supermarket chains - Pingo Doce - the one I would always visit, Minipreco - a smaller but cheaper one, and Continente - bigger but a bit more expensive one.

Unwrapping and first meal
I had to share the 4-room apartment with 3 others. However, I had arrived before everyone else. Therefore, I had the whole apartment for me for a few days. We also had a portion of an open-air balcony that belongs to us, that we later used for barbecues and parties. Our apartment was surrounded by 3 metro stations - Saldanha, Alameda, and Arroios. Alameda neighborhood has a beautiful park with a water fountain. For the first few days when I was still alone in Lisboa, my life was mostly limited to this triangle where I was walking around. I realized how much time I had saved while living in Sri Lanka, thanks to my parents who were doing many things for me - such as cooking, grocery shopping, and taking care of managing everything that does not need me personally. Now I am on my own, and I had to spend time doing a considerable amount of 'boring' things such as cleaning and grocery shopping. However, since the environment is new, I was still excited. I did feel like a fish out of water at times. My mom had gifted me a God Ganesh statue before I left Sri Lanka, which I had taken with me to Lisboa. The God Ganesh always secured a spot in all my apartments in Lisboa and elsewhere afterward.

1.2: Feeling young 
2012 September - 2012 December
Campo Pequeno
Eventually, my three apartment mates arrived, and we lived like a team during our stay. Our landlord also made sure to help every one of us settle in, with the bank accounts, school administration, and initial shopping. He went above and beyond, showing us the spirit of Portuguese hospitality. We all went to the same university, and our university was at a walking distance. My classmates of the same Erasmus Mundus program arrived soon after, and the courses began on the 17th of September. We all became good friends, as we all had come from various parts of the world. Thanks to Erasmus Mundus, we all had a clique though. No one was left around.

The Alameda Park, in front of IST
The early days, i.e., the year 2012 was exciting. Everything looked new and fresh.  I had visited France (Paris), India (Bangalore and Hyderabad), and USA (Mountain View/Googleplex) before. But this was my first experience living abroad. Luckily I was not alone in this journey, and it was pleasant!  During my first year in Portugal, I maintained a weekly blog on my life in Lisboa. Everything seemed new and fresh, and I never ran out of things to blog about. We tried to learn Portuguese. I even got a certificate for the A1 level. However, my only regret in Portugal was not truly learning Portuguese. I never realized I would stay in the country for around 7 years. Indeed, it was not a continuous stay of 7 years — more of an on-and-off stay due to the Erasmus Mundus mobility requirements. Still, Portugal was my base country for the entire period. My initial plan was to stay just a year. But this lovely country and circumstances made me stay much longer.

Cascais Beach - my first beach outside Sri Lanka
We spent some time visiting popular places in and around Lisboa. We used the yellow bus, the Lisboa's version of the hop-on-hop-off buses you would find in any major cities. We paid visits to major museums and churches. Belem, Estrela, Oceanario, Sao Jorge Castle, Sintra, and Cascais/Estoril beaches - all those popular touristic destinations in Lisboa. Sao Jorge Castle, despite being within the city limits, feels like otherworldly. Sintra is just outside Lisboa. It is blessed with the beauty of nature and architecture. Lisboa Oceanario is undoubtedly one of the best in the world. Cascais beach was clean and nice - but later I would visit much better beaches in Portugal. We do not have a metro in Sri Lanka. I started to getting used to (and love) the metro journeys in Lisboa.

IST/ULisboa - Alameda Campus
Our EMDC program was a coordination of 3 universities - IST/Lisboa, UPC/Barcelona, and KTH/Stockholm. While half of us spent the first year in Lisboa, the other half was in Barcelona. We all would meet in KTH/Stockholm for the third semester, before breaking away for the thesis in the 4th/final semester. I also became the Erasmus Mundus Association (EMA) program representative (PR) for EMDC. It was fun, representing EMDC. Later, I also represented EMDC and EMJD-DC at EMA in the following several years and organized EMA days and participated in an EMA General Assembly.

Taguspark Campus
Some of our classes in the first semester were in Taguspark. A long shuttle journey twice a week also became part of our life. Taguspark is in the middle of nowhere. So when we had lectures there, we had to spend the whole day on the campus. Luckily, the Tagupark canteen offered relatively good food. All you can pick at once with a fixed price. We also had some good memories and made some local friends at the Taguspark campus. The Taguspark campus was also more modern than the Alameda one. Later during the Ph.D. I had the Data Quality course in Taguspark - thus reliving those Taguspark memories after 2 years.

Praca do Comercio
In Saldanha, right next to our campus was "Canela e Acucar", a cafe restaurant that offered cheap food, starting from 4.45 Euro. Bacalhau, the salty dry cod fish is a popular Portuguese food that we tried often. We also had several fish including Carapasinhos (the small fish, fried), Dourada, and Robalo. We also had other options such as Francasinhas. We learned one thing quick. If you ask for "Sumo de Laranja" you will get some orange soda. Not the real orange juice. You must ask for "Sumo de Laranja natural" for freshly squeezed orange juice for like 2 Euro or 2.50 Euro. The orange juice maker was virtually in every cafe in Portugal. We liked to have orange juice as it is natural and 100% orange. No water, sugar, or anything else added. The Civil department canteen food was 4.50 Euro, with daily options for 3 Euro food also. Then there were also subsidized canteens for students in the main building, as cheap as 2.35 Euro. We tried all the canteens - their food options and desserts.

Arraial Do Tecnico
Despite our busy schedules and group projects, we still had lots of fun. Our university also hosted some interesting events, such as the annual musical evening of Arraial Do Tecnico. Music, snacks, and beer. That was fun. Thanks to our diverse friends, we even had our own "cultural days" or international students' days - including a Chinese party and a Brazilian party. We also visited the Hindu temple close to Telheiras in Lisboa, as well as the mosque in Sao Sebastiao! As time passed by, I experienced my first autumn in Lisboa - much wetter and colder than the summer. I enjoyed my first Halloween in Lisboa, meeting new friends.

Bairro Alto
Every Friday evening we would visit the "Erasmus Corner" in Bairro Alto where we have beers and some drinks and meet other exchange students as well as some locals. Bairro Alto hosts the Erasmus Student Networks and an Erasmus Bar. The place had a unique smell of beer, Portuguese and international food, and the occasional smell of urine from some corners. Bairro Alto is popular for its cheap beer - 1 euro per cup. Bairro Alto neighborhood was also special for me - especially the view from the corridor where I had a birthday celebration in 2013.

Christmas at Rossio Square
By the end of 2012, we got more familiar with the city. We had to apply and receive a residence permit, which we then had to renew every other year. We started to visit more interesting not-so-touristy places as well. Lisboa indeed has some hidden gems such as Pensão Amor. We also enjoyed our first Christmas in Lisboa, despite the approaching exams. The exams and group project presentations were a little bit stressful - but we all overcame them successfully. No one was left behind. I also started the habit of writing an annual post, summarizing my interesting events (typically limited to 30 events each year, a number I randomly chose) of the year.

1.3: Those Days
2013 January - 2013 June
2013 New Year - It all started here
My first new year in Lisboa was exciting. Despite the exams, I decided to do a big shopping, because I was so energetic. I also had received my scholarship money. So why not? Falling in love in Lisboa was a wonderful feeling. The experience was mesmerizing. We recall the new year of 2013 and the romantic memories of Praca do Comercio (with the Terreiro da Paco metro station) every now and then. After several years, we still fondly recall those first 6 months of 2013 as "those days".

On the way to Freeport from Oriente
I also had started to travel outside Lisboa. I first visited  Fatima with 2 of my Sri Lankan friends. It was an average Portuguese village, if you remove the religious significance. But it was also my first trip in Portugal outside Lisboa. Therefore, it was special to me. During these days, EMDC also had our Winter Event in Nuria, Spain. We met our EMDC mates from Barcelona for the first time. It was also our first international trip from Lisboa. We traveled to Madrid and Barcelona and stayed in cheap youth hostels - dorm rooms and bunk beds. We enjoyed the snow and a real winter of -11 C. It was also my first time getting drunk. In my entire life, I had got drunk only twice. First in Barcelona (2013) and then in San Francisco (2016). Strong memories.

Romantic Parque das Nacoes
Not all walks are memorable as our extended weekend (Thursday evenings - Monday mornings) walks. Parque das Nações had become our regular romantic getaway. We walked by the riverside, from Cabo Ruivo, Oriente, Moscavide, and until Sacavem. Over the years, we witnessed how the Parque das Nacoes neighborhood evolve. We visited all the restaurants along the river. Some restaurants later closed down and new ones, including a fancy Chinese restaurant appeared years later. We also visited the newly popping up restaurants in Parque das Nacoes. We fed the seagulls close to Oceanario and also fed the geese in Estrela park. I got used to walks and metro rides between my university (IST) and ISCTE-IUL. We also frequented the Hard Rock Cafe in Restauradores and Starbucks in Rossio train station, as they both are close to each other. In the blue metro line, we also visited Santa Apolonia. The photos bring back vivid memories.

Drinks at Hard Rock Cafe Lisboa
Arroios neighborhood had a Dim Sum restaurant. Although the service was bad, the food was good. Therefore, we visited it several times. There was also a Chinese buffet restaurant, which was similar to every other Chinese buffets in Lisboa. There was also a Portugalia that we visited once. Estefania neighborhood, in between Arroios and Saldanha was a good one for a walk from our apartment. We used to buy lots of things from Pingo Doce and take them back home. Eventually, we also started to visit the nearby Continente.

A night walk in the Avenida neighborhood
We watched several movies. At times, two movies back-to-back in the same day in the same shopping mall. We also had the loyalty cards from the movie theatres! There was also a night we decided to stay in the streets just outside Centro Comercial Colombo after a late night movie from 2 am until 6.30 am when the metro station eventually opened. Yes, we were crazy. :) I also started cooking in Lisboa. Initially I started for fun and to save money. I became quite good with cooking eventually. I actually was enjoying cooking various interesting recipes. First I followed the recipes to the letter. Later, I started to innovate. I used to post photos of my cooking to Facebook, until I retired from Facebook in 2015 December. Eventually, as I started cooking, I reduced the freqeuncy of my visit to the Nepal restaurents. However, I would still take my friends to a Nepal buffet.

Beautiful view of Obidos
My first spring in Lisboa was refreshing and romantic. We made boat trips to cross the Tagus river, which separated Lisboa from most of everything. From Cais do Sodre port, we would take a boat to Cacilhas in the other side of the Tagus river. From Cacilhas, then we take a bus to the beach towns such as Costa da Caparica. We attempted our best to see dolphins in Setubal. But we failed several attempts. ;) Óbidos was a town that we loved visiting - its cherry wine / ginjinha (ginja) in a chocolate cup was truly unique, best of both worlds. We played Chess there while enjoying some ginja in a romantic hotel (Pousado do Obidos). We visited Obidos once again later for its chocolate festival. We also went to the Freeport open-area shopping mall twice, taking the bus from Oriente.

Typical Portuguese food along the river
We frequented many good restaurants in the city. There was a Nepal restaurant, Restaurante Kathmandu, in our road. I was frequenting it, especially because it was the closest to Sri Lankan food I was able to get while in Lisboa. I took many of my friends to that restaurant at several occasions. I also visited some other Nepal restaurents. We also frequented Restaurente Destino, a friendly restaurant in Restauradores neighborhood. We would often walk from Restauradores to Avenida, along Avenida da Liberdade.

Porto Matosinhos Beach
Finally, the summer was back to Lisboa again. By this time, I decided that I would come back to Lisboa for my master thesis. Therefore, my stay in Lisboa is not going to be limited to just one year. :) We also started to feel the pain of friends saying goodbye, as the semester ended. Some were in Lisboa for just one semester! I would love it if every wonderful people stay with me, and not to leave in the middle. :) But life is always moving.

My move to Stockholm came close too. I had to go to Sri Lanka before that. We visited Porto and Lagos before I left Portugal. Saying goodbye is hard. But I reassured I would come back. Since we were spending time in Porto and Lagos before I left Lisboa, time went real quick when we were finally back in Lisboa. I came to Lisboa 10 months back with a free memory. I left Lisboa with a strong association to the city. I knew I would be back soon.

1.4: Party Never Ends
2013 August - 2013 December
Vila Franca de Xira riverside walk
While I was in Stockholm, I visited Lisboa twice. First, immediately after arriving in Stockholm, to enjoy the summer in Lisboa and Setubal. Then, during the mid-semester break, which was already wet autumn in Lisboa. During my second visit, we also made a metro station trip, visiting each and every neighborhood connected by Lisboa's extensive metro line - that we had missed previously. We also visited Alcantara-Terra, the touristic riverside of Lisboa. We also visited Vila Franca de Xira by train. It is a riverside town that can be reached by the train from Lisboa that goes towards Azambuja. The town hall had a free open wifi by the riverside in the town. But when I visited the town later, the wifi was no more open for public.

The beautiful Lagos
When I am away from Lisboa, I often think of the days I spent there. Despite my 7 years there, most of my memories revolve around 2013 - specifically those days, the first 6 months there. The memories are addictive and intense, and they are like a drug - I can feel the blood circulations with the memories. My memories of Portugal also is correlated with a few songs I listened to during my stay in Portugal. There are a few songs, mostly of Romanian origin - I always associate them with those romantic memories of Lisboa - because I listened to them for the first time during those days. Some songs bring back the memories of youthful moments, nostalgia, and the longing feeling that is defined as Saudade in Portuguese.

I always made sure to revisit the places that I loved visiting such as Obidos and Evora. But I never revisited Porto and Lagos later. Therefore, those memories are sealed as the memories of 2013 summer. But I, of course, want to revisit Porto and relive those memories. It will always be like time traveling to 2013 if I revisit Porto or Lagos. On the other hand, the place may still be the same. But it may not be possible to recreate the exact moments. We can try.