Making stuff fast at @redpandadata.
Joined December 2018
- Tweets 12,555
- Following 176
- Followers 4,196
- Likes 5,692
435 Photos and videos
Pinned Tweet
11 Jun 2019
Do you like footnotes? Do you like long, rambling lists?
Then, this might be the thing for you:
travisdowns.github.io/blog/2…
There, I smash my personal footnote count record (20). As for lists? It has lists *within* lists. The only thing left is to write it in LISP.
15
63
252
Travis Downs retweeted
6 Jan 2025
The latest release of the simdutf C library (6.0.0) brings in more convenient for C 20 users. While you used to have to provide both a pointer and a size parameter... often you can now just pass your container...
std::vector<char> data{1, 2, 3, 4, 5};
// C 11 API
auto cpp11 = simdutf::autodetect_encoding(data.data(), data.size());
// C 20 API
auto cpp20 = simdutf::autodetect_encoding(data);
Link in the comments.
4
2
45
4,825
Travis Downs retweeted
17 Aug 2024
to our friends/companies downloading #redpanda 1.5M times a day... should turn on caching 😂
2
4
27
3,585
24 Nov 2023
So we have LLMs that border on indsiguishable from real people (well, this depends in part on the company you keep) but autocorrect on my phone is still awful, making mistakes a toddler could correct.
Is it a latency problem?
12
23
5,703
We're excited to hear @redpandadata's Travis Downs describe the practical experience of building high performance systems with C 20 in an asynchronous runtime. He'll also discuss tradeoffs in adopting a thread-per-core architecture. bit.ly/43RHzlV
#P99CONF #ScyllaDB
2
11
38
4,480
17 Oct 2023
Despite the expansive title this is mostly a quick look at coroutine performance for those who are interested in that kind of thing.
10 Oct 2023
📣 WATCH REDPANDA AT #P99CONF
Join @trav_downs this Oct 19th to learn all about our adventures in thread-per-core async with Redpanda and #Seastar.
It's a virtual event, so all you have to do is register👇
p99conf.io/
3
8
22
11,036
Travis Downs retweeted
11 Nov 2022
For a long time I've been thinking that using a closed loop (sync) for measuring latency is wrong
3
31
194
Travis Downs retweeted
10 Nov 2022
Measuring the memory usage of your C program lemire.me/blog/2022/11/10/me…
2
23
138
Travis Downs retweeted
27 Oct 2022
some pretty cool tests we are doing on the #redpanda cloud of aggregate throughputs of 40GB/s. nbd .... more deets to come on Nov 15th. hopin.com/events/redpanda-op…
thanks to @trav_downs for the goodie you see below.... maybe we should do a 200GB/s test next? 🤣
#kafka
26 Oct 2022
There is always something special about seeing a 30GB/s #redpanda cluster (10GB/s producer writes 20GB/s for replicas). Very cool 😎
3
10
29
Travis Downs retweeted
13 Oct 2022
10-20GB/s yes. We don't have anyone at 40GB/s yet. 400GbE not yet, but DM me if you want to test. This is the reason we have a dedicated Performance Engineering team
x.com/trav_downs/status/1575…
29 Sep 2022
Do you count cycles in your sleep?
Do you sweat over those last few μsecs?
Do you both love and hate Nagle's algorithm?
Join me in making future of event streaming wicked fast!
@emaxerrno has built a team of great people here at Redpanda and we're looking for a perf expert.
1
1
9
New ARM instructions were just released! (With SVE 2.1, among many other things)
(I always use the exploration tools, but you can view them online too: developer.arm.com/documentat…)
developer.arm.com/downloads/…
2
20
81
29 Sep 2022
Do you count cycles in your sleep?
Do you sweat over those last few μsecs?
Do you both love and hate Nagle's algorithm?
Join me in making future of event streaming wicked fast!
@emaxerrno has built a team of great people here at Redpanda and we're looking for a perf expert.
6
13
56
29 Sep 2022
You can find additional details and apply here:
boards.greenhouse.io/redpand…
Alex's (@emaxerrno) and my DMs are always open for any questions, or (in my case) just random performance chit-chat is well received too.
1
6
Travis Downs retweeted
26 Sep 2022
While everyone is enjoying all the #AMD #Zen4 performance reviews, here is my teardown of Zen4's #AVX512 implementation and architecture.
tl;dr - Intel has some serious competition now.
mersenneforum.org/showthread…
12
85
371
28 Aug 2022
Hey @AMD release the @AMDRyzen Zen 4 optimization guide already.
Keeping this under wraps is just a dead loss isn't it? A weird "we hate people optimizing for our chips too early" thing.
17 Aug 2022
they release zen 4 architecture optimization guide a month ago, zen 4 is just a deeply optimized zen 3.
2
10
47
Travis Downs retweeted
26 Aug 2022
y-cruncher v0.7.10 coming out soon with Zen4 AVX512 optimizations.
This was fun since there are no optimization resources yet for this chip. Had to do all the RE myself.😅
6
14
134
New blog post: Faster zlib/DEFLATE decompression on the Apple M1 (and x86)
dougallj.wordpress.com/2022/…
ALT Graph of decompression performance, showing zlib-dougallj outperforming 3 alternatives by about 50% on each of the files in the Silesia Corpus. zlib-cloudflare is consistently second best, closely followed by zlib-ng, with zlib-apple further behind, outperformed by about 2x. The files have been compressed with zlib level 6, and throughput is measured in compressed mb/s on M1 using Apple clang 13.1.6. zlib-dougallj performs between 282 and 380mb/s, cloudflare performs between 186 and 276mb/s. xml: apple 122, ng 181, cf 194, dj 290. x-ray: apple 181, ng 190, cf 209, dj 330. webster: apple 132, ng 195, cf 205, dj 303. sao: apple 234, ng 260, cf 276, dj 380. samba: apple 151, ng 211, cf 221, dj 321. reymont: apple 131, ng 210, cf 213, dj 338. osdb: apple 173, ng 206, cf 224, dj 352. ooffice: apple 142, ng 170, cf 186, dj 291. nci: apple 119, ng 171, cf 191, dj 282. mr: apple 164, ng 187, cf 208, dj 329. mozilla: apple 153, ng 187, cf 199, dj 307. dickens: apple 148, ng 219, cf 238, dj 344.
16
41
201
Travis Downs retweeted
1 Aug 2022
Given:
1. crc32 has throughput 1 on port 1
2. pclmulqdq has throughput 1 on port 5
3. pclmulqdq pxor can emulate crc32
It seems that fastest crc32 code should divide input in half and issue a crc32 _and_ a pclmulqdq every cycle.
Code and numbers at corsix.org/content/fast-crc3…
1
18
51
Travis Downs retweeted
23 Jun 2022
Filtering numbers quickly with SVE on Amazon Graviton 3 processors lemire.me/blog/2022/06/23/fi…
10
34