trishume

5 ms·

1.
by trishume 8mo ago
Author of the take-home here: That's quite a good cycle count, substantially better than Claude's, you should email it to performance-recruiting@anthropic.com.
2.
by trishume 3y ago
I haven't actually used bpftrace myself, only BCC. I can totally imagine it being more janky than DTrace, BCC is pretty janky even if I also think it's cool. In my eBPF tracing framework I had to add special handling counters to a
3.
by trishume 3y ago
Do you know of anyone who's built that kind of time travel debugging with a trace visualization in the open outside of Javascript? I know about rr and Pernosco but don't know of trace visualization integration for either of them,
4.
All my favorite tracing tools(thume.ca)
355 points by trishume 3y ago|40 comments
5.
by trishume 4y ago
To me most interesting are factors I didn't consider in features I did cover. Next most interesting are features I didn't cover which are kinda core to Twitter being good, and also pose interesting performance problems, like the p
6.
by trishume 4y ago
That's really cool! Each year of historical images I estimate at 2.8PB, so it would need to scale quite far to handle multiple years. How would you actually connect all those external drive chassis, is there some kind of chainable SAS
7.
by trishume 4y ago
I have fantasized about doing this as a startup, basically doing cache coherency protocols at the page table level with RDMA. There's some academic systems that do something like it but without the hypervisor part. My joke fantasy star
8.
by trishume 4y ago
I think I'm pretty careful to say that this is a simplified version of Twitter. Of the features you list: - spam detection: I agree this is a reasonably core feature and a good point. I think you could fit something here but you'd
9.
by trishume 4y ago
Which I think I'm perfectly clear about in the blog post. The post is mostly about napkin math systems analysis, which does cover HTTP and HTTPS. I'm now somewhat confident I could implement this if I tried, but it would take many
10.
by trishume 4y ago
I agree most HTTP server benchmarks are highly misleading in that way, and mention in my post how disappointed I am at the lack of good benchmarks. I also agree that typical HTTP servers would fall over at much lower new connection loads. I
11.
by trishume 4y ago
Yah like I say in the post, the exactly one machine thing is just for fun and as an illustration of how far vertical scaling can go, practically I'd definitely scale storage with many sharded smaller storage servers.
12.
by trishume 4y ago
Quote tweets I'd do as a reference and they'd basically have the cost of loading 2 tweets instead of one, so increasing the delivery rate by the fraction of tweets that are quote tweets. Hashtags are a search feature and basically
13.
by trishume 4y ago
My friend mentioned this just before I published and I think that probably is the fastest largest thing you can get which would in some sense count as one machine. I haven't looked into it, but I wouldn't be surprised if they coul
14.
by trishume 4y ago
I specifically assumed a max tweet size based on the maximum number of UTF-8 bytes a tweet can contain (560), with a link to an analysis of that, and discussion of how you could optimize for the common case of tweets that contain way fewer
15.
by trishume 4y ago
As the author, this sounds good to me! I'll probably even change the actual title to match. I originally was going to make it a question mark and the only reason I didn't is https://en.wikipedia.org/wiki/Bette
16.
Production Twitter on one machine? 100Gbps NICs and NVMe are fast(thume.ca)
776 points by trishume 4y ago|477 comments
17.
by trishume 4y ago
Oooh nice! Your Kyria posts are actually where I first learned about how awesome and cheap SendCutSend is, and got some of the inspiration for the magnets. I actually ordered a plain steel plate first, but I realized that given that I neede
18.
My DIY ergonomic travel workstation with aluminum and magnets(thume.ca)
215 points by trishume 4y ago|89 comments
19.
by trishume 4y ago
The latency numbers they state seem achievable or beatable with Infiniband, Amazon's EFA, or TCPDirect. 2us round-trip is achievable for very simple systems. If this kind of networking sounds good to you, you can buy it today! It'
20.
by trishume 4y ago
This is a really cool example of tree diffing via path finding. I noticed that this was the approach I used when I did tree diffing, and sure enough looks like this was inspired by autochrome which was inspired by my post ( https:/&#x2
21.
by trishume 4y ago
I really hope he can work with cloud vendors and Intel to make Processor Trace a more popular and easier to use capability. It's unfortunate how https://github.com/janestreet/magic-trace and PMUs in general can&#x
22.
Magic-trace: Diagnose tricky performance issues with Intel Processor Trace(blog.janestreet.com)
170 points by trishume 5y ago|18 comments
23.
by trishume 5y ago
https://www.figma.com/ and putting a lot of effort into them
24.
by trishume 5y ago
Have you seen my Xi CRDT writeup from 2017 before? https://xi-editor.io/docs/crdt-details.html It's a CRDT in Rust and it uses a lot of similar ideas. Raph and I had a plan for how to make it fast and memory effic
25.
by trishume 5y ago
This is awesome. In theory you could absolutely minimize the latency penalty to just the overhead of the gpu1->memory->gpu2 copy, if the display sync signals from the display the passthrough window was on were passed through to the GP
26.
by trishume 5y ago
I really hope we get more technical information on how Lumen and Nanite work, and additionally that Epic doesn't patent the techniques in either of them. A patent on either would make me so sad, 20 years is really long in software, abs
27.
by trishume 5y ago
Standard Fenwick trees can only do prefix sums, which only get you general range queries on things with a subtraction operator, not operations like maximum. The reddit comment I link contains an implementation that allegedly does arbitrary
28.
by trishume 5y ago
Cool! I thought about using skip lists a bunch before I settled on this, trying to think of various ways to reduce complexity and memory usage. My best skip lists designs still had some pointer overhead that the implicit approach avoids, bu
29.
by trishume 5y ago
Yah mipmaps are an N-dimensional generalization of the breadth first layout of implicit aggregation, where the aggregation function is averaging. It may in theory be possible to generalize the in-order layout I talk about in a similar way,
30.
Implicit In-order Forests: Zooming a billion trace events at 60fps(thume.ca)
175 points by trishume 5y ago|24 comments

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