Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ask HN: What are you working on (September 2024)?

news.ycombinator.com

Post reply on HN
Print view View original

801–810 of 1001 posts

Re: Ask HN: What are you working on (September 2024)?

#801

Post by bediger4000 »

kmoser wrote: post #404
bediger4000 wrote: post #31

Trying to figure out a bizarre performance drop in a merge sort I wrote for one of those daily coding problems. https://bruceediger.com/posts/mergesort-investigation-1/ It seems that adding one node to a linked list causes a repeatable performance drop. That is, linked lists of say 2^21 nodes sort faster than lists of 2^21 + 1 nodes.

Does it have to do with when garbage collection is triggered?

I don't think so. There's no garbage generated during the sort, which is what I'm timing. I'm sure that GC runs during the sorts, but it won't do significant amounts of work because of that.

A C-transliteration of my original Go algorithm shows similar overall performance, with performance drops at the same list lengths.

Forcing garbage collection right after each sort (releasing all references to the sorted linked list) didn't change anything, either: https://bruceediger.com/posts/mergesort-investigation-10/

Re: Ask HN: What are you working on (September 2024)?

#802

Post by mmcool »

A marketplace that makes booking a hair transplant overseas easier! Why overseas? Because, not only are they are 10-15k cheaper outside of the US. The quality is better! Doctors overseas do hair transplants every day as opposed to the states where they may only do once a month.

Anyways, I am trying to make sure people only go to reputable clinics, and eventually let them pay online (instead of carrying cash). Check it out!

https://doctours.health

Re: Ask HN: What are you working on (September 2024)?

#803

Post by retardracer »

Hey Guy, i built a website/domain security scanner tool. SSl/TSL, WAF detection, Secure Cookies, HSTS, DKIM/DMARC, DNSEC, etc..

I think the security score are gimicky (ignore that i have a header score I will be removing that).

You can just use it as a one-off tool to scan/check, you can schedule scans, get notified of changes (unexpected or expected), show proof of remediation, auto JIRA issue creation (with PDF attaching).

Thoughts? I would love some comments/usage/feedback. internetsecure.org

Re: Ask HN: What are you working on (September 2024)?

#804

Post by seidleroni »

A website that sorts the recent Peloton bike rides by difficulty. https://pelohard.com/

I love my Peloton and it was really annoying finding a ride with a difficulty over a certain threshold that was recent. I'm an embedded developer by day and did this with a lot of help from ChatGPT and Claude. Hoping to add some more features to it as time goes on.

Re: Ask HN: What are you working on (September 2024)?

#805

Post by Bloedcoins »

retardracer wrote: post #803

Hey Guy, i built a website/domain security scanner tool. SSl/TSL, WAF detection, Secure Cookies, HSTS, DKIM/DMARC, DNSEC, etc.. I think the security score are gimicky (ignore that i have a header score I will be removing that). You can just use it as a one-off tool to scan/check, you can schedule scans, get notified of changes (unexpected or expected), show proof of remediation, auto JIRA issue creation (with PDF att…

it doesn't explain the findings very well. What exactly is it, how to configure it etc.

Re: Ask HN: What are you working on (September 2024)?

#806

Post by bediger4000 »

poorlyknit wrote: post #549
bediger4000 wrote: post #31

Trying to figure out a bizarre performance drop in a merge sort I wrote for one of those daily coding problems. https://bruceediger.com/posts/mergesort-investigation-1/ It seems that adding one node to a linked list causes a repeatable performance drop. That is, linked lists of say 2^21 nodes sort faster than lists of 2^21 + 1 nodes.

The fact that it happens 1) at/around powers of two 2) regardless whether using GC or preallocating makes me think its got to do with cache sizes. For example, the M2 macbook has around 16MiB of cache, which gives you approximately 2 million ~ 2^20 nodes where each node has a 64 bit number and a 64 bit pointer. The jumps in your measurements could be related to the cache hierarchy. On Linux (probably macOS too) you s…

Thanks for reading my blog post and thinking about it. I thought of cache as well, the 3 machines I'm running benchmarking on are all very different. The M2 Macbook has 128-byte cache lines, as opposed to the other 2 machines, which have 64-byte ache lines. The old Dell R530 has level 1 through 3 caches, the others have only levels 1 and 2. I'm still trying to understand CPU caching and see if I can correlate it to the performance drops somehow.

The linked list nodes are 16 bytes, and both 8-byte fields (.Next and .Data) get read and written during sorting. Up to a point, larger node sizes,which I would thing would change caching, don't change where the performance drops occur: https://bruceediger.com/posts/mergesort-investigation-7/

Sorting an already sorted, or reverse sorted list, doesn't exhibit the performance drops either: https://bruceediger.com/posts/mergesort-investigation-9/

A purely recursive mergesort doesn't show the performance drops: https://bruceediger.com/posts/mergesort-investigation-3/

Re: Ask HN: What are you working on (September 2024)?

#807

Post by Bloedcoins »

ianthehenry wrote: post #204

https://bauble.studio/ is a programmatic 3D art playground that I've been working on for a while now, and I'm pretty excited about it! It's based around signed distance functions, which are a way to represent 3D shapes as, well, functions, and you can do a lot of like weird mathematical distortions and operations that give you cool new shapes. Like average two shapes together, or take the modulo of space to infinitel…

this is really great: https://mastodon.social/@ianthehenry/113223607547344491

How did you do it? Whats the shading factor?

Re: Ask HN: What are you working on (September 2024)?

#809

Post by [deleted] »

mmcool wrote: post #802

A marketplace that makes booking a hair transplant overseas easier! Why overseas? Because, not only are they are 10-15k cheaper outside of the US. The quality is better! Doctors overseas do hair transplants every day as opposed to the states where they may only do once a month. Anyways, I am trying to make sure people only go to reputable clinics, and eventually let them pay online (instead of carrying cash). Check i…

[deleted]

Re: Ask HN: What are you working on (September 2024)?

#810

Post by retardracer »

Bloedcoins wrote: post #805
retardracer wrote: post #803

Hey Guy, i built a website/domain security scanner tool. SSl/TSL, WAF detection, Secure Cookies, HSTS, DKIM/DMARC, DNSEC, etc.. I think the security score are gimicky (ignore that i have a header score I will be removing that). You can just use it as a one-off tool to scan/check, you can schedule scans, get notified of changes (unexpected or expected), show proof of remediation, auto JIRA issue creation (with PDF att…

it doesn't explain the findings very well. What exactly is it, how to configure it etc.

I tried to give a little description, on each one but I can do better (and I made them smaller because i thought it was too much text!

thanks for the tip/idea. I want to have a HELP page that might give more details into each check, a sample .htaccess or similar that you can just drop in and secure most things up (but with possibly breaking functionality in your site ha but just to have that option).

Its to just show your current state/posture.

Post reply on HN