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redraga

255 karma · joined July 22, 2010

url: www.cs.umn.edu/~natar twitter: @redraga
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redraga··on Tom Scott: After ten years, it's time to stop making videos [video]
I completely agree with this observation. In fact, you can use this to your advantage to save time. During the pandemic years of 2020 and 2021, Blizzard released "Classic" World of Warcraft and I had this huge itch to play the game. I satisfied it by watching YouTube videos on Classic WoW instead.

Did I waste time watching WoW YouTube videos? Yes. Did I save much more time by tricking my brain into thinking I was playing the game when I actually wasn't? Yes!

redraga··on Mr. Beast Deepfake Scam
Would a public/private signature for videos work in solving such fakes? If not, why not?
redraga··on Ask HN: What you up to? (Who doesn't want to be hired?)
I've started playing around with the idea of building a better retirement/goals investment calculator/tracker for Indians.

The retirement calculators available online are almost farcical in their simplicity and assumptions. And the ones offered by professional, fee-only financial advisors (I engaged one) are just clunky, uneasy to use excel sheets. They do the job of course, but I think there has to be an easier, more intuitive way to tracking goals/investments.

I know way too many of my friends and acquaintances - educated, fairly wealthy people - who seem to have almost no idea on how to plan/track goals/retirement. It'd be fantastic if I could make something which helps them and others like them.

redraga··on Ask HN: What's the most life-changing blog post you've ever read?
Two posts from Astral Star Codex

* A THRIVE/SURVIVE THEORY OF THE POLITICAL SPECTRUM [1] - Still the best theory on the conservative/liberal divide. It changed how I view the conservative viewpoint and helped me understand it better.

* MEDITATIONS ON MOLOCH [2] - One of the most famous blog posts on the internet (certainly in HN circles at least). Part fantasy, part philosophy, part game-theory - all of it brilliant. It changed how I approach my life goals and what I need to optimize for in life. A blog post so famous that it has it's own podcast[3]!

[1] https://slatestarcodex.com/2013/03/04/a-thrivesurvive-theory...

[2] https://slatestarcodex.com/2014/07/30/meditations-on-moloch/

[3] https://open.spotify.com/episode/7yGVsF2VPi4knhfRujM1Yx?si=q...

redraga··on Indian Government proposes to buy bulk subscriptions of all scientific journals
I wasn't aware of this. The model actually works great since I've personally accessed multiple papers from INRIA/IRISA from the HAL archives.
redraga··on Why is Apple's M1 chip so fast?
I can't really comment on the tradeoffs between specific ISAs since I've mainly worked on micro-arch research (which is ISA agnostic for most of the pipeline).

As for the questions on research into looking at decode complexity v instruction density tradeoff - I'm not aware of any recent work but you've got me excited to go dig up some papers now. I suspect any work done would be fairly old - back in the days when ISA research was active. Similar to compiler front-end work (think lex, yacc, grammar etc..) ISA research is not an active area currently. But maybe it's time to revisit it?

Also, I'm not sure if Huffman encoding is applicable to a fixed-size ISA. Wouldn't it be applicable only in a variable size ISA where you devote smaller size encoding to more frequent instructions?

redraga··on Why is Apple's M1 chip so fast?
I can't comment on the economics of it but I can comment on the technical difficulties. The issue for x86 cores is keeping the ROB fed with instructions - no point in building a huge OoO if you can't keep it fed with instructions.

Keeping the ROB full falls on the engineering of the front-end, and here is where CISC v RISC plays a role. The variable length of x86 has implications beyond decode. The BTB design becomes simpler with a RISC ISA since a branch can only lie in certain chunks in a fetched instruction cache line in a RISC design (not so in CISC). RISC also makes other aspects of BPU design simpler - but I digress. Bottom line, Intel and AMD might not have a large ROB due to inherent differences in the front-end which prevent larger size ROBs from being fed with instructions.

(Note that CISC definitely does have it's advantages - especially in large code foot-print server workloads where the dense packing of instructions help - but it might be hindered in typical desktop workloads)

Source: I've worked in front-end CPU micro-architecture research for ~5 years

redraga··on A history of branch prediction
Yes. TAGE still does better than perceptron, but combining the two is likely to give you the best performance currently. Of course, all this is dependent on area allocated to the predictor and the workloads being run.
redraga··on Bloody Plant Burger Smells, Tastes and Sizzles Like Meat
I'd say most vegetarian Indian food has the problem of excess starch and carbs. One potential reason for the wide prevalence of diabetes in India.
redraga··on How to do a PhD
While this is completely valid advice, it might not be applicable with junior faculty who may not have graduated many students. I chose my advisor (who was as assistant professor at the time) based on the belief that I'll get to publish aggressively since it's in both of our interests. But I had no way of knowing how hard it would be to work with her. And I wasn't the only person who felt this way; I saw my fellow group mates (all of us joined the group at around the same time) and other collaborators express similar sentiments in course of time. But since I'd already sunk in time, I decided to stick around.

I was able to successfully complete my PhD, but I took more time than expected. Moreover, I was no way near as productive as I'd hoped to.

redraga··on Fears over the true state of China's economy
I've heard this view echoed by friends who've visited China (I'm Indian). A major reason for this difference might be the fact that China opened up its markets in the late 1970's while India's market liberalization happened only in 1991.
redraga··on Who ordered memory fences on an x86? (2008)
Remember that x86 (and SPARC) offer the strongest memory ordering guarantees among modern processors. The POWER and ARM memory models are weaker than x86. This actually leads to correctness issues when virtualizing a multi-core x86 guest on a weaker host (cross-ISA virtualization). Of course, this problem only shows up in truly parallel emulators using multiple threads on the host to emulate a multi-core guest, such as COREMU (http://sourceforge.net/projects/coremu/)
redraga··on Who ordered memory fences on an x86? (2008)
>The appropriate uses of mfence are actually much more limited

This is true for regular race-free multithreaded programs. However, mfences are used fairly commonly in lock-free, concurrent data structures (http://concurrencykit.org/)

redraga··on How do you get to write so well in HN?
While this is a good way to learn about things in depth, I'd be wary of overusing it. It could have detrimental effects when commenting on topics way outside your domain knowledge (lower comment quality or worse - a misinformed comment). Also, it limits the scope of topics that you might end up developing an interest in.

Interestingly, the way I consume articles and forums is almost completely opposite. I skim through anything that catches my fancy, which helps me discover new topics that are interesting to me, and I only contribute when I have something completely new and valuable to add to the discussion. Often times you find that someone has already mentioned what you wanted contribute. The exceptions are when you are an expert in the field and hence more likely to have knowledge that is not common.

redraga··on Ask HN: Best salary negotiation tip?
Here's a great write up on salary negotiation by patio11: http://www.kalzumeus.com/2012/01/23/salary-negotiation/
redraga··on U.N.C. Investigation Reveals ‘Shadow Curriculum’ to Help Athletes
European football (soccer) teams run academies of their own to groom players. If a youngster is serious about becoming a professional footballer, he/she joins these academies. They are given a "well-rounded" education, but the emphasis is obviously on the sport. Graduates end being signed by the parent club, or getting contracts with lower-level teams if they can make the cut.

I'm curious to understand why this system isn't practiced in the US.

redraga··on What kids around the world eat for breakfast
You forgot one of my favourites, Akki rotti - savory stiff crepe made from rice
redraga··on ARM’s Rebuttal to RISC-V: “The Case for Licensed Instruction Sets”
> Also, is binary ISA translation restricted by patents?

Intel has binary translation software to run ARM apps on x86 phones, so I'd guess it's not limited by patents.

redraga··on The Cost of My Mother’s Cardiac Care in the United States and India
> For lawsuit-related reasons, I'd avoid doing such a startup myself.

Of course, I think this is an idea that Indian based startups can pursue.

redraga··on The Cost of My Mother’s Cardiac Care in the United States and India
The sentiment that teaching and medical practice are noble professions is widespread in India. Both these professions command a lot of respect in society.
redraga··on The Cost of My Mother’s Cardiac Care in the United States and India
Looks like there's a good opportunity for medical tourism in India. Maybe it's a startup idea?
redraga··on Books that have stayed with us
I've never read GEB. Can you elaborate on how it helped you become a programmer?
redraga··on Stories from our first two years
Donors have an option of "tipping" Watsi apart from the donating to the patient's treatment. But I'm not sure if this alone covers their operating costs.
redraga··on At Multiverse Impasse, a New Theory of Scale
A lot of discoveries do not have immediate uses and some might indeed never have any applications. But discoveries can spurn others in unexpected ways. The most famous example of course if the WWW which came out of CERN, a pure physics research institution. Cryptography is another example that has had a profound impact on information security. But the most compelling reason, at least to me, is we investigate because we can! That is just human nature.
redraga··on RISC creator is pushing open source chips
From my experience certain applications, mainly server workloads, have a high instruction footprint. I-cache optimizations are necessary even on an x86 processor. So there might be some weight to this argument. I'd like to see the difference in behavior between the two architectures.
redraga··on Eating Healthily for $3 a Day
I'm an Indian, and lentils are one of the main ingredients in vegetarian Indian cooking. Mostly because they are the main source of proteins. I've never had any...problems with the force. But it might be because of conditioning.
redraga··on [dead]
Link to the map (http://i.imgur.com/c6Agr.jpg)
redraga··on Teen Mathletes Do Battle at Algorithm Olympics
I highly recommend solving problems on spoj.pl (http://www.spoj.pl/). It has a HUGE collection of problems from various competitions, supports a plethora of languages for coding and the forums are an excellent resource.
redraga··on Bing Overtakes Yahoo as the #2 U.S. Search Engine
All that aggressive advertising looks like it has paid off. And competition is always good for any market.
redraga··on How I boosted my Vim
Great guide! My .vimrc had most of these settings, but I picked up a few things that made life much easier. Below are some tricks that I use which might make useful additions.

Binding the <Esc> key to capslock has been really useful for me. http://vim.wikia.com/wiki/Map_caps_lock_to_escape_in_XWindow... explains how you can do this, although it's done externally and not in Vim. Just include the script in your shell rc file and you're good to go.

Experienced users can hide the menu and tool bars with:

set guioptions-=m "remove menu bar

set guioptions-=T "remove toolbar

Extra screen space for your code is always nice!

Another amazingly useful plugin is MiniBufExplorer (http://www.vim.org/scripts/script.php?script_id=159). This allows you to open multiple buffers in the same vim window, and with the key binds given in the plugin page you can switch between buffers just like you switch between tabs in Firefox. It's really useful when you follow tags in a large source directory.

And for people who can't seem to find just the right colour scheme: Color Scheme Pack plugin (http://www.vim.org/scripts/script.php?script_id=625). It has over a 100 different themes, nicely categorized.

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