This blog

May. 31st, 2019 10:08 am
izard: (Default)
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 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 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: , , , and
izard: (Default)
Very typical ad I found in our neighborhood.

A long story with photos of tenants looking for a flat. (This is an exception - usually there are no photos, or story is shorter).
I bet they won't find a flat..
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I am not getting clojure zip, that is so sad. Here is a trivial function:

REPL> (def atree (list 1 2 3 (list 4 5) (list 6)))
REPL> (rm-from-tree atree 10)
(1 2 3 (4 5) (6))
REPL> (rm-from-tree atree 3)
(1 2 (4 5) (6))
REPL> (rm-from-tree atree 5)
(1 2 3 (4) (6))
So far, so good.
REPL> (rm-from-tree atree 6)
NullPointerException clojure.core/with-meta--4375 (core.clj:218)


Upd: works fine if I replace list with vector.. WTF??!!1111


Aug. 14th, 2017 05:54 pm
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Interesting findings :) [profile] blau_kraehe(lj only) was writing about similar things before, but now in New York Times :)
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Very spectacular thread on gizmodo. A google's s/w engineer writes a long and boring piece about inclusion and positive discrimination. The original text is so perfectly crafted internet troll bait, that I am 100% certain he was dead serious. Comments and responses are great, I especially liked this one: "if you were in my reporting chain, You would have ... a much smaller meeting, including you, me, your manager, your HRBP, and someone from legal. And it would have ended with you being escorted from the building by security and told that your personal items will be mailed to you."

This all reminds me left dissidents in late USSR, who were trying to start an open theoretical discussion about a paths to communism in a Soviet Union.

Upd: As expected, they fired the guy.
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We were flying a brand new SSJ100 from Moscowo to Nizhny and back, and windows were very clear.

Approach to Sheremetievo :

Read more... )
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A dialog between 3 years 1 month old Jacob and his mother Yulia:
- Черт, не надо было мне открывать дверь почтальону!
- Мама, ты ошиблась? Мама, ты - дура?
- Яша, нехорошо так говорить о маме!
- Когда папа ошибется, я скажу - папа, ты дурак!
- Ну если ты так правда думаешь, то говори хотя бы про себя.
- Про меня? Но я не дурак!
- Про себя - это беззвучно, чтобы другие на слышали, очень тихо.
Яша ставит указательный палец вертикально перед ртом, и очень тихо шепчет: "Мама, ты дуура."
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Jacob is now 3 years and one month old. Since 2 and a half, one of his favorite phrases is "Это не смешно" - he uses it very often to describe any situation he does not like. Yulia and me were never using this phrase, so I was always wondering where he picked it, considering that he is exposed to a very limited set of Russian speakers.

Today I got it - it is simply his translation of "Es ist nicht lustig", a phrase that he often hears in a kindergarten.
izard: (Default)
I am back from Russia. I don't come there often, so each time I notice a visual difference.
For example, advertisements change a lot between my visits. 2 years ago, there were many
grafitti tags "dial 8-9xxxx to buy cheap viagra/cialis". Now the very first ad I've seen upon
arriving to Sheremetievo airport was "buy pills ZZZ, to make your male orgasm brighter and
more colorful.". I hope those in double blind controlled clinical trials for this substance had some fun.
And I wonder how they measured. Oh, I guess there was no clinical trials.. The pills are made in Nizhny Novgorod,
it was written in the ad btw. Also this time I seen more tags like "dial 8-9xxxx to buy salt/pepper/nutmeg" (for those who don't know, they don't mean salt/pepper). Sad.
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It is his second time in Russia, but now he is old enough to understand a bit more.
- Mama, Papa, what is it? - pointing at a hole on an asphalt pavement.
- It is a hole.
- A hole? Who makes such holes? Why they make them? How they make them? May I touch it?
At 3 years and 1 month old, it is a first time he discovered a hole in asphalt that is not a part of a fenced construction area :)
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Finally, live feed from Skylake-SP launch. Yes, it does not have SHA-NI, but it is the biggest improvement in u-arch since Nehalem.


Jul. 11th, 2017 12:20 pm
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The worst kind of bugs - 3rd party libs dependencies..
On a fresh Fedora 26 install on one of my test servers, one of the tools I needed wanted to install some gtk and gdk dev libs.
# yum install ...
"you are about to install a ton of deps, tolal 100Mb" Y/n
A tool works.
Now I need to install a kernel src package:
# yum install ...
File "/bin/yum", line 57, in
from dnf.yum import main
ImportError: /usr/lib64/python3.6/site-packages/rpm/ undefined symbol: PySlice_AdjustIndices
Previous installs broke yum!

Very cool: I can't even google PySlice_AdjustIndices, and PySlice library simply does not have AdjustIndice method in 3.6.0, only SetIndices...

Of course I don't care to debug deeper (or file bugs with Fedora), it is just easier to re-install.
izard: (Default)
I have to admit that I was wrong - when I first read about roofline model several years ago I thought it is too abstract to be used in a real s/w performance work.

It is not, and Intel Advisor tool that visualizes loops in roofline model actually more makes sense than I thought.
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- Пусть мама сродит мне братика!
- Почему не сестренку?
- Девочки лучше, но с ними сложнее, а у мамы сил нет.
- А с братиком придется делиться ресурсами?
- Игрушками? Я старше, так что он у меня отнять не сможет, а я у него смогу. Но я своими буду делиться, иногда, ненадолго. А ему ты будешь тоже игрушки покупать, а я у него брать.
izard: (Default)
Yesterday Akhilesh Kumar, the Skylake-SP CPU architect announced mesh architecture for future Xeon CPU,

that replaces ring. The ring was there in Xeon for 6 generations, and once the server CPU has grown from 4 to 20+ cores, latency of the ring became an important factor to consider in software performance work. In last 4 architectures, there were even sub-rings (Cluster-on-Die) to address this. Some folks were reverse-engineering a secret (though simple) hash function that directed different cache lines to different chunks of last level cache.

No need any more. That is just one of great features in the upcoming CPU.

The circle

Jun. 5th, 2017 02:03 pm
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After [profile] blau_krahe suggestion, I just read it during this long weekend. The narrative style in Russian is very similar to "Холодная зона" by the way.

It is fun to read, but unlike "Холодная зона", everything in this book seems just trivial. First 20% or so is absolutely realistic, then as the plot becomes somewhat darker in the following 10% of the book, the rest 70% becomes obvious. So I guessed all the remaining plot after I read the first 30%, just thinking: "What would an american author write to make absurdity grow until a possible maximum is reached." I think if the author would have been european, it would not be that easy.

So in a hindsight, I would recommend reading the first 30% of this book, skipping all the rest but last 5 pages or so.


Jun. 4th, 2017 09:08 am
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Ants can't reach young leaves of a beech next to our home, so all the sugar aphids produce just crystallises on leaves.

Very tasty :)
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I got a weird problem with a neighbour, that demonstrates a typical German way of communication. My wife needed some room in a trunk of our car for shopping, so she removed a folding stroller from the trunk, and left it at our parking lot. (The parking place at our building's underground parking that belongs to us). In couple of hours Yulia came back, and did not find a stroller. She looked around and found it ~20 meters away, at some other neighbor's parking lot.

In the evening, I found a letter (with date, name and signature) under my car's wiper:

"Hi, I accidentally rolled over a stroller that was lying at your parking lot. Now I have some scratches on my car, if the stroller belongs to you, please call me +49NNN to discuss the compensation."

I wonder what I do next, obviously my German is not good enough to discuss these matters over phone, and Yulia would not stay calm during the conversation (though even if it turns out to be our fault, we still have an insurance for that).

I am also very curious, what would happen in US and Russia in the same circumstances?

work stuff

May. 22nd, 2017 04:19 pm
izard: (Default)
1. Looks like openvswitch constantly monitors PMUs, so it is difficult to monitor it's performance externally :(
2. I was asked to explain why sharing workload to 2 cores with 80% utilization was equivalent to sharing it to 6 cores with 40% utilization. Kinda funny, shouldn't it be obvious?
izard: (Default)
2 years 11 months old, riding on my neck:
- Я всадник! Я - полицейская конная стюардесса!
(перечислил все любимые профессии)
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