Log in

izard's Journal

Recent Entries

You are viewing the most recent 25 entries.

31st May 2019

10:08am: This blog
I'm writing the blog in English because I type twice as fast this way than in Russian (yes I am improving...), and 90% of my friends and friends can read English any way. I answer comments in the same language they are posted.

I am trying not to post anything related to my employer, but if I do so, this expresses only my own views and does not represent an official position of my employer.

When I post about some technical topic which seems non trivial and is related to my employer's product, don't expect it to be inside information. If I post about it, it means that this info is already public. Usually I do not post any personal information or anything that is related to my family.

All photos are mine, and I allow anyone to copy, change, do anything you please with them. I don't post "friends only".

Useful tags are: software , idea , Deutschland, freediving and trip report

3rd February 2016

1:37pm: Useless knowledge
I got 256GB RAM in my workstation. So I booted with 100 1GB hugepages for guests.
Then I found out that flock(3)(fd of "/dev/hugepages") blocks forever. However when I allocate only 32 1GB hugepages it works.

If I investigate it further, I might discover and report a bug in kernel, but probably I won't: now I just know how to deal with it..

2nd February 2016

6:57pm: ?
Munich police, official facebook page :
"Einer der Fahrgäste filmte die Auseinandersetzung mit seiner Handykamera und veröffentlichte die Aufnahme später auf seinem Facebook Account. In dem dazu von ihm veröffentlichtem Text beschrieb er die Vorkommnisse mit eigenen Worten. Weder meldete er den Vorfall der Polizei, noch erstattete er eine Anzeige.
Ihr habt eine starke Polizei an eurer Seite. Aber in solch einer Situation nicht den Notruf 110 zu wählen, erschwert uns die Arbeit und gefährdet eure Sicherheit.
From the facebook of the author of a viral video
"Ich bin der Urheber dieses Videos. Leider hat die Pressestelle der Polizei München hier eine Fehlinformation verbreitet. Ich bin zuerst auf die Polizei zugegangen, nicht die Polizei auf mich. Dies werde ich in Kürze genauer darlegen sowie mit der Pressestelle Kontakt aufnehmen, um dies richtigzustellen."

Of course, I do not have any way to find out which of sentences in bold is correct, but they are mutually exclusive.

1st February 2016

12:59pm: Another great article on cache u-arch
A very nice piece of reverse engineering of the algorithms used by last level cache in recent Intel CPUs, source code included.
Here it is. Of course, if you are frontend developer, it should not matter for you.

29th January 2016

11:10am: Good hard sci-fi
A good novel in Russian. Alas, the author only accepts webmoney not paypal. Upd: http://alex-anpilogov.livejournal.com/90257.html

28th January 2016

2:05pm: Road code q.
Germans are usually very good drivers. They are courteous, obey the rules (and sometimes break rules, where it is good for safety or has a neutral effect). I am not a good driver. So I wonder what can be wrong with my actions on a crossing, that happens nearly every daily commute. My car is marked red.

Left lane goes only straight, middle lane can go straight or turn right on a left lane, and right lane can go only right on a right lane. That is how I understand it, when I turn right from a middle lane. (Right lane usually has a long line of cars waiting for the green light, and middle lane usually has 0-2 cars only, mostly they are going to go straight.

So why I always have to brake as hell because a car from the right lane goes straight to a left lane on turn? If there is a crash there, who's fault would it be?

19th January 2016

11:13am: Lufthansa M&M - no more.
Istanbul-Munich, 125 status miles (100 miles + 25 silver status bonus). That is a line from my recent LH M&M status statement. My mileage traveled by LH & Star Alliance is ~constant since 2006 when I got a job that requires some travel. I got ~40-50k status miles each year (except the year when Jacob was born so I traveled less).

This allowed me to keep LH silver status and enjoy several perks, sorted by importance: 1. Having breakfast/lunch/dinner in a business lounge in Munich before departure. 2. Board early on flights from US to Munich, so I can put my stuff to the overhead bins. 3. Very rare upgrades to business class, usually that was special offers to spend award miles.

Not any more, I think 2016 is the last year I keep my silver card. In 2006-2012 it took just 2 flights 2 US per year and couple of local flights to keep silver status. Now LH gives much less miles for that (I think for my flight to Portland I planned in March I will only get ~2k miles).

14th January 2016

4:17pm: German civil engineers
I am a huge fan of a sticky tape myself, and use it all the time in the lab and IRL.
But this one is epic:

I would understand if it was a temporary measure for a few days, but several light poles next to my home look like that for 3 months already :). I suspect it is permanent fix.

4th January 2016

12:47pm: Lightbulb moment in a US consulate
Professor: How many lightbulbs are in this room?
Student, counting: 6!
Professor, getting a lightbulb from his pocket: wrong, 7! Come another time.
Another time.
Professor: How many lightbulbs are in this room?
Student, counting: 6+1, 7!
Professor: wrong, I don't have an extra one in my pocket! Come another time.
Student: But I do, so it is 7!

US Consulate, 3 years ago:
Consul: You are an engineer, your visa application needs special administrative processing in US. Please bring us your CV, patents and publications list, and we will only give you 1 year visa.
me: ok, more delays.
US Consulate, 2 years ago:
Consul: You are an engineer, your visa application needs special administrative processing in US. Please bring us your CV, patents and publications list, and we will only give you 1 year visa.
me: Here it is, I have it all.
Consul: I cannot take it, we need electronic copies only, please send us e-mail, and we will only give you 1 year visa.
me: ok, more delays.
US Consulate, today:
Consul: You are an engineer, your visa application needs special administrative processing in US. Please bring us your CV, patents and publications list, and we will only give you 1 year visa.
me: Here it is, I have it all. Or do you need an email? I have it all prepared, can send at once.
Consul: No we do not process emails any longer, I need hardcopies but I cannot take them now, you need to send them by mail.
me: ok, more delays.

3rd January 2016

3:24pm: Last day of NewYear holidays :(
Tomorrow I'll go to US embassy to renew my US visa (I bet they will send my file for administrative processing as usual, so I got my CV, patents and publications list handy). Then will go to the office to fix plenty of bugs I have in my latest DPDK code that SIGESGVs like hell in random places in a AVX2 library.

Yesterday we watched Star Wars with Yulia, and I liked it how all the audience was laughing through the film. The loudest laughter happened when GrandSonOfDarthVader opened his helmet.

1st January 2016

1:34pm: Freediving stats
About sports. I am doing this for leisure, but still interesting to see how I compare to others.

These are the standards:
AIDA 1 Star Freedive, 8m CWT, 1'15" STA, 25m DYN.
AIDA 2 Star Freediver, 16m CWT, 2' STA, 40m DYN.
AIDA 3 Star Freediver, 24m CWT, 2'45" STA, 55m DYN.

My current stats: 12m CWT(Eilat'2015), 1'40" STA(home, should be better when mammalian diving reflex kicks in in water), 35m DYN (~1.5 25 meter pool laps, no fins. So with fins should be 3 stars actually). Should be straightforward to get to 2 stars, but I don't see any realistic progression path towards 3 star let alone 4 star..

31st December 2015

3:20pm: 2015.
2015: Jacob is growing. Very funny to observe him learning russian vocabulary and grammar.

Q1: Intel IOT devkit: Hackathon in Romania, demo at Embedded World, enhancements, customer PoC.
Q2: A lot of politics, as a result I moved back to work on Intel servers from embedded. Good vacation. I am almost at a ~2 stars AIDA freediving, and it seems like I'll never approach 3 stars (which is fine.)
Q3: Getting back to speed at new old job, travelling to old new peer teams. Working on stuff to deliver in Q4.
1. Great trip to Israel to help a customer, solved a bug that was investigated by tens of engineers for almost 2 months. It appeared to be not a bug in a product I support but a very nice combination of Linux kernel and BIOS bugz :)
2. Delivered a keynote at a programming conference - very different experience in preparation and run comparing to speaking on some particular technical topic.
3. Delivered a talk on Virtualization performance issues at Linuxcon.
4. Implemented an interesting enhancement to DPDK, hope to submit a patch in Q1.
5. In Q1, I decided that Java support is important, and implemented basic Java support for Intel IOT devkit middleware. The team implemented the rest (that is second 90% of the work), and it was released at JavaOne.

2 patents on real time stuff I submitted few years ago are now in "published" state at USPTO web site. Waiting if they would be granted.
Published some stuff on habrahabr and software.intel.com. Will keep posting in 2016.

1. got 2 original XZ Spectrums from ebay working. Sometimes I run my sweet old games.
2. Also bought couple of ancient ICs from 70s on ebay, but only made one work: a very first SRAM chip.
3. Downside: still struggling with an FPGA dev board, failing to run anything but trivial samples.
4. Unfortunately I did not find any time to code something fun as I hoped. But instead I played with my son a lot, that was great.

Thanks a lot dear colleagues, sorry I probably can't spell names here because of privacy concerns. But you all are on Facebook anyway :)

14th December 2015

12:46pm: За хлебушком вышел.
Shopping on Sunday here is nearly impossible. Sometimes I drive to Edeka in the airport, but usually I can buy everything we need on Saturday. This shopping ban has some merit that I can understand.

However after nearly seven years living here yesterday I discovered yet another nuance of this Sunday shopping ban.

Very often on a Sunday a go to a bakery to buy fresh bread. Yesterday I was a bit late and when I entered to the bakery it was 11.15. It should be fine: on Sundays some bakeries are still open until early afternoon.

So I asked if I can buy a loaf of bread and some cookies. The answer was: "yes, here are your cookies, but we are not allowed by law to sell bread after 11AM on Sundays. We will remove it from the shelf at once.." I checked another bakery, and it was the same! Wtf? There should be some reason! If there is already staff employed who sells cakes, why not sell bread too?

9th December 2015

10:33am: Management styles
The great book on management published by CIA in 1940s is now freely available at internets!

The book starts with
"The purpose of this paper is to characterize simple sabotage, to outline its possible effects, and to present suggestions for inciting and executing it." And then it goes along about the best management practices that some people have first hand experience with.

"Acts of simple sabotage... Slashing tires, draining fuel tanks, starting fires, starting arguments, acting stupidly, short-circuiting electric systems, abrading machine parts will waste materials, manpower, and time" - oops, that is not about the management yet. I'll have to read a next chapter.

"Adjust the overload relay to a very high value beyond the capacity of the motor. Then overload the motor to a point where it will overheat and break down." Still not the right chapter..

Oh, here it is (my personal favourite in bold):
1. Insist on doing everything through "channels." Never permit short-cuts to be taken in order to expedite decisions.
2. Talk as frequently as possible and at great length. Illustrate your "points" by long anecdotes and accounts of personal experiences.
3. When possible, refer all matters to committees... Attempt to make the committees as large as possible — never less than five.
4. Haggle over precise wordings of communications, minutes, resolutions.
5. Refer back to matters decided upon at the last meeting and attempt to re-open the question of the advisability of that decision.
6. Advocate "caution." Be "reasonable" and urge your fellow-conferees to be "reasonable" and avoid haste which might result in embarrassments or difficulties later on.
7. Be worried about the propriety of any decision — raise the question of whether such action as is contemplated lies within the jurisdiction of the group or whether it might conflict with the policy of some higher echelon.
8. See that the important jobs are assigned to inefficient workers...
9. Insist on perfect work in relatively unimportant products; send back for refinishing those which have the least flaw.
10. To lower morale and with it, production, be pleasant to inefficient workers; give them undeserved promotions. Discriminate against efficient workers; complain unjustly about their work.
11. Hold conferences when there is more critical work to be done.
12. Multiply paper work in plausible ways.
13. Multiply the procedures and clearances involved in issuing instructions, and so on. See that three people have to approve everything where one would do.
14. Apply all regulations to the last letter.
15. Spread disturbing rumors that sound like inside dope.
16. Never pass on your skill and experience to a new or less skillful worker.
17. If possible, join or help organize a group for presenting employee problems to the management. See that the procedures adopted are as inconvenient as possible for the management, involving the presence of a large number of employees at each presentation, entailing more than one meeting for each grievance, bringing up problems which are largely imaginary, and so on.
18. Act stupid.

I think 18 is redundant actually provided that 1-17 are in place.

1st December 2015

3:24pm: За нашу и вашу свободу.
Here is a very good writing example.

"We fight [abroad] so you can protest against us [at home]"
Today I seen news in German TV about sending Luftwaffe planes to Syria, so it reminded me of this ad.

The ad is located on a bus stop next to our home. (Actually, it is ~300 meters away. There is one which is closer, but it has two official markings on it. “Bus stop” and “This is not a bus stop”. Weird.)

27th November 2015

10:04am: New Spectrum for Christmas
Here it is, arrived and works perfectly.

The 128K "toastrack edition". I always wanted to get 128K Spectrum, but my upgrade path was 48K Spectrum clone -> i80286 based PC. Now finally, after 25 years of waiting I got one!

Anyone remembers a game on the screen? Hint: I don't think there were any games of this spectacular genre released since.

25th November 2015

4:03pm: Programmers hiring ad in U-Bahn
Today there was snow lying on the ground in the morning. And as usual, S-bahn did not work, I still don't get it why it happens every year.

So I had to take U-bahn train to the office, which is much slower and more crowded. But my stop was the last one, so when I was about to exit a train I was able to make a pic of an ad:

They are hiring C++ developers, it looks. I wonder why not Javascript/Scala/Ruby, or what is the language that is now in favor or hipsters/front end devs?

20th November 2015

5:51am: An inquiry, bugz
Two days ago I flown to Tel Aviv to solve a technical puzzle. Now I am in Ben Gurion airport waiting for the departure.

And the puzzle is solved. This was one of the more rare lucky events of Veni, vidi, vici, that do not happen too frequently, so I'll describe the reasoning we used.

In the first 4 hours on Wednesday, I've formulated three hypotheses about what has caused a huge and unexpected software performance regression reported by customer : some code is misusing an architecturally visible CPU feature (1), an OS kernel bug that triggers an issue with u-arch that is normally benign but not in this case (2), or OS kernel bug that is just a crazy kernel bug (3).

Yesterday morning a team of customer's engineers and me started to investigate all three, trying to find a proof for each in parallel. One engineer was developing an OS driver that should spot (1). I was gathering more data to proof (2). Another engineer was gathering more data so I could formulate a question about (3) to the OS kernel team. Another engineer was running all the required tests on multiple SUTs, and a project manager was bringing me sweets, fruits and fresh juice, and communicated with stakeholders.

By lunch, I was done with a half of (2). Indeed there was a performance degradation caused by this reason, but only for ~11%, not 5x. Another half could have contributed ~20% more at most, but this was it.

I did not expect that fast turnaround, but the device driver which checked for (1) was ready by 4PM. We checked it and found that (1) is true, and caused by (3). We discussed the prospective fix, and when we came to a conclusion I estimated that if I was developing a fix it would have taken me ~1 full work day. The engineer who developed a tool to check (1) opened the tool's source code, added ~100 more lines of C code in 20 minutes, compiled, got a compiler error, fixed, compiled, ran, got a runtime error, fixed, compiled, ran, and the issue was resolved! It took less than an hour. (Others called him a genius, and I tend to agree that I only meet coders of this caliber just once or twice per year.)

But Israelis! Experts in bargaining. It was 5PM and the issue was resolved. So they told me: by the way, we have another issue, not as critical but let's solve it too. Reluctantly I ran Vtune, just in case enabling its newest feature of collecting some other stuff besides normal PMU events. And it worked - the first run shown a root cause of another strange issue that appears quite rarely. (Has yet to be confirmed with other tools). Yesterday it was just a lucky day!

19th November 2015

7:49am: Enjoying travel
On Tuesday night, I had a call that I need to urgently go to Israel. So at 11PM I bought a Turkish Airlines ticket, and at 6AM yesterday I was checking in to my flight at a Munich airport. At 4PM yesterday I was already at a customer office, and for 4 hours we were investigating a very strange performance issue, that has its roots very deep in a very low level details of CPU implementation. This is one of 2 strange low level issues I have on my active list. The first one is nearly solved thanks to very valuable help from shipilev and a linux kernel maintainer I should not name here.

By 8PM we've collected enough data to start reasoning, but I went to my hotel to check in and sleep over it. Today from 6AM till 8AM I plotted ~20 graphs in Excel that try to explain the data I got, and now I have 3 hypothesis to check today.

Writing this while having a breakfast outside a sunny cafe on Izhak Rabin square in Tel Aviv :) Really enjoying the weather after Munich.. Alas, flying back tomorrow at 5AM.

16th November 2015

5:21pm: Efficiency
Yesterday when I was walking to a swimming pool I have seen some excellent driving:
11.25. A police car with lights on passes an intersection at ~100kph, and then turns to Rosenheimerstr towards Rosenheim.
11.26 another one.
11.26 operative police car follows. (one they just put the lights on top of an ordinary car)
11.27 another one
11.30 a medevac helicopter is flying fast towards Klinikum Rechts der Isar.
I guess it was an accident at the start of the autobahn, but why sending an operative car there?

14th November 2015

10:30am: New article on s/w performance
I recently published a new article on NFV performance at Intel web page. I think all stuff I wrote is trivial, but nevertheless it made it to my todo list this summer.

The last chapter on TSX was heavily edited by Roman Dementiev, the best TSX expert I know.

Another cool thing about the article are links at the bottom. E.g. a video on how to set up prox in Vritual machine - cool stuff for quick and easy dataplane performance modeling.

13th November 2015

8:48am: Hare beware
Today it was a second time my s-bahn ticket was checked by a rather unusual crew.

Usually ppl who check tickets in S-bahn are clearly visible. They are uniformed - either as railroad security or as railroad workers. Bags they carry also look the same. Any sane person who rides without a ticket will just see them and exit the train. (Though I am always surprised when they catch someone, mostly about how clueless this ppl are.)

This groups is very different. They dress very, very casual. They wear different and cheap backpacks. They have diverse origins - one African, 3 middle eastern, including a lady.

They ride a stop or two, then instantly approach 5 passengers they think are a good bet.

You would never think they are the people to come to you, show the document and tell: "Die Frhrscheine, bitte!". I guess they collect ~5x more fines than traditional crews.

May be MVV now just chose franchising business model for ticket control?

11th November 2015

5:44pm: Lufthahsa strike
Because of a strike,

my flight to a customer got cancelled (again) and I ended up spending 9 hours in a train today, and had to wake up t 5AM. Bastards.

8th November 2015

8:25pm: Equality rant
Usually I change diapers for my son, especially when we are out. He weights ~11kg now so for me it is easier than for Julia. Our today's walk in the parK reminded me of an equal rights problem..

(As always I don't post pics of Jacob or Julia in the blog)

There are only 3 options in public places, e.g. malls or airports or parks: men's restroom with a changing table and women's restroom with a changing table, special changing room, and men's restroom w/o changing table but women's restroom with a changing table. So what should I do in the later (good it is not too common) case?

7th November 2015

9:35pm: Woodpecker
This is not the best picture of a woodpecker I have,
but I shot it from my window at home. Now Jacob knows a word "дятей" and waits if a woodpecker would fly near the window again.
Powered by LiveJournal.com