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

A summary of my EMDC 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.

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.

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℃.

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. 

However, 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.

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! Most of us had a reunion there meeting our friends after a long time. 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. :)

Monday, April 8, 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!

Tuesday, April 2, 2019

Memories of Portugal

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. My landlord was waiting for me at the airport with my name on his iPad. He showed me around. I had to share the 4-room apartment with 3 others. However, I had arrived before everyone else. Our apartment was surrounded by 3 metro stations - Saldanha, Alameda, and Arroios (as years passed by, Arroios was shut down for renovations and yet to be reopened). For the first few days when I was still alone in Lisboa, my life was mostly limited to this triangle where I was just walking around. 

Eventually, my apartment mates arrived. Three wonderful people, and we lived like a family during our stay. Our landlord also made sure to help everyone 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 in 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 arrived from various parts of the world. Thanks to Eramus Mundus, we all had a clique though. No one was left around.

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. We 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. In fact, it was not a continuous stay of 7 years. But more of an on-and-off stay due to the Erasmus Mundus mobility requirements. Anyway, my initial plan was to stay just a year. But this lovely country and circumstances made me stay much longer.

We spent some time visiting the popular places in and around Lisboa. We used the yellow bus, the Lisboa's version of the popular hop-on hop-off buses you would find in any major cities. We paid visits to the major museums and churches. Belem, Estrela, Oceanario, Sao Jorge Castle, Sintra, and Cascais beach. We do not have metro in Sri Lanka. I started to getting used to (and love) the metro journeys in Lisboa.

Some of our classes in the first semester was 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 in the campus. Luckily, the Tagupark canteen offered relatively good food. We also had some good memories, and made some local friends at the Taguspark campus.

Despite our busy schedules and group projects, we still had lots of fun. Our university also hosted some interesting events, such as the annual Arraial Do Tecnico. That was fun. 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. Thanks to our diverse friends, we even had our own "cultural days" or international students' days. ;) We also visited the Hindu temple in Lisboa! 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.

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-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 of the year.

My first new year in Lisboa was exciting. Despite the exams, I decided to do a big shopping, because I was so energetic. Falling in love in Lisboa was a wonderful feeling. We frequented many good restaurents in the city. The experience was mesmerizing. After several years, we fondly recall those 6 months as "those days". Parque das Nações became our regular romantic getaway. I got used to walks and metro rides between my university (IST) and ISCTE-IUL. We also frequented the Hard Rock Cafe. We watched several movies. I started cooking in Lisboa. Óbidos was a town that we loved visiting - its cherry wine / ginginha in chocolate cup was truly unique, best of both worlds. 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. We attempted our best to see dolphins in Setubal. But we failed several attempts. ;) 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. :)

I also started to visit places outside Lisboa, such as Fatima. 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 good bye is hard. But I knew I would come back.

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.

Currently being updated....

Visiting new places vs revisiting - new vs old memories. My desire to revisit Porto.

My memories of Portugal also is correlated with a few songs I listened to during my stay in Portugal.

Life is like a chess game. You play it against the unknown. The unknown is everything else and everyone else that can affect or influence you. You plan your moves which make your life choices and decisions. But you can just guess what the unknown's next move will be. Only after the opponent's (in this case, the Unknown) move, you realize whether your move was a good one or rather, a bad one.

Parque das Nações, Almada, Porto, and Lagos.

Sunday, March 17, 2019

[GSoC] Google Summer of Code Frequently Asked Questions

GSoC has its own Frequently Asked Questions. However, students always come up with more interesting questions that deserve a personalized answer. I decided to compile my own FAQs for GSoC based on my past 5 years as a mentor. Some answers may be subjective and reflecting based on the organizations that I have worked with (AbiWord/4 years, OMII-UK/1 year, and Emory BMI/4 years).

Please note that Google can change its policies each year. In case of a conflict, Google has the final say in the GSoC policies (obviously!). :)