maxhou

7 ms·

1.
by maxhou 11d ago
I tried switching a buildroot based CI server to the 26.04 One Makefile statement triggered a bug in rust ln: src/%: @ln -sfn $(DIR)/foo src In parallel build, we would get random failure: ln: Already exists Re
2.
by maxhou 5y ago
implementation of continue from one luajit fork: https://github.com/zewt/LuaJIT/commit/c0e38bacba15d0259c3b77...
3.
by maxhou 9y ago
Yes they do. A read() syscall takes longer than a getpid() syscall because read() has more work to do, it actually does a data copy of len bytes, which takes some time (and will be faster/slower if data is cache hot) What we call the &
4.
by maxhou 9y ago
How do you know that the dataset fits in L2 ? Assuming pv uses splice(), there is one only copy in the workload: copy_from_user() from fixed source buffer to some kernel allocated page, then those pages are spliced to /dev/null. I
5.
by maxhou 9y ago
yes and pv processes are not scheduled on the same CPU core, so different L2 cache.
6.
by maxhou 10y ago
Does the protocol implement any kind of negotiation (ciphers, ...) ? if not, how would you handle future type of attacks against the then hardwired constructions ? I fully agreed that being in-kernel is the right choice for performance, but
7.
by maxhou 10y ago
> what ORM to use (or not to use an ORM) do you have something to recommend ? used Rose::DB in the past, then I discovered SQLAlchemy and it's difficult to look back...
8.
by maxhou 11y ago
http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_260.htm
9.
by maxhou 11y ago
> Suppose, for example, that you go to the Bank of America site to transfer some funds or pay a bill. As with Google, and as would happen with any other secure site, it turns out their certificate gets replaced with the Avast certificate
10.
by maxhou 11y ago
It won't help. To serve its purpose, any AQM (active queue management) like fqcodel must be done at the congestion point. The end-user computer has a faster link than its internet connection upload speed, typically a gig ethernet where
11.
by maxhou 11y ago
from the article: > Each core needs to generate a few thousand data packets per second, because Ethernet packets typically contain up to 1500 bytes. This gives the CPU around 100 microseconds to process each packet. No it doesn't, n
12.
by maxhou 11y ago
You forgot the cost of memory access. The L3 layer checksum is useless because IP packet is small and the kernel has to read/write all the fields anyway. The L4 checksum covers TCP/UDP packet data, which the kernel can avoid touch
13.
by maxhou 11y ago
simple checksum computation and/or verification, indeed most cards can do (sometimes with restrictions: not for IPv6, not for VLAN...) the other kind of offloading that the kernel can use is TCP Segmentation Offload (TSO), which is muc
14.
by maxhou 11y ago
I'd have expected a small easteregg for the word "bro" ;)
15.
by maxhou 11y ago
The most obvious is that they have multiple cores, and it's easy to completely disable a non functional one. Now can Intel be more granular than the core level, like running a core with some defect ALU, I really don't know. What&#
16.
by maxhou 11y ago
> And if one atom is in the wrong place, you have to throw away the chip this is certainly the case for CPU but DRAM & NAND ? this is the typical case of designs where you can add redundancy to accomodate for manufacturing defects.
17.
by maxhou 11y ago
if you use mmap(), there is virtualy no difference between the streaming/non streaming parsing code.
18.
by maxhou 11y ago
In the real world, the slow part of "parsing" a CSV file is IO: reading the file content from disk to memory, and from memory to CPU cache. You would avoid reading the file content more than once if you had to parse it. > The f
19.
by maxhou 12y ago
Except parsing all the Android.mk and computing the dependencies is slow as hell. Try running make at the top of an AOSP tree, it takes about 60 seconds, and that part cannot be parallelized. If you are looking for alternatives, have a look
20.
by maxhou 12y ago
OP says the system was swapping. Once your hash table and its linked lists have been swapped to disk, each pointer dereference causes a random disk access, which are orders of magnitude slower than RAM.
21.
by maxhou 12y ago
The problem is that all NAT related issues are not because of NAT itself, but because of the required stateful firewalling for NAT. To be able to NAT and un-NAT, you first need to classify traffic (that NEW, ESTABLISHED, RELATED,... stuff i
22.
by maxhou 12y ago
Or maybe the opposite ? If you charged Netflix, they would consider investing more money on trying to reduce the bandwidth they use: - innovative video codec - better encoders - new streaming technology
23.
by maxhou 12y ago
ENOSPC ?
24.
by maxhou 12y ago
actually since none of its tests ask to sync the data onto the disk, he might just be measuring each method efficiency in creating dirty pages. of course that depends on the amount of RAM the system has, and how the kernel VM parameters are
25.
by maxhou 12y ago
> My theory would be the cost in terms of space and electricity to generate 10Gbe of video streams has dropped orders of magnitude Spot on. You can stream video with basically nginx serving static files, you just need a 10G network card
26.
by maxhou 12y ago
How about asking for net neutrality on DDOS traffic ? I find it unfair that my ISP is shaping it ! :)
27.
by maxhou 12y ago
True, but people claiming: "I pay for XXX Mbit/s, I want my XXX Mbit/s 100% of time to 100% of the Internet" think/want the Internet to operate like that.
28.
by maxhou 12y ago
> Having enough capacity to meet the streaming demand of your current customers during peak times is a solvable problem that doesn't require a full gigabit for everybody, all the time. With adaptive streaming technology, there is no
29.
by maxhou 12y ago
at least my ISP term of sales is clear about it, the guaranteed bandwidth is close to 0. I do agree though that nowhere in the commercials it is said that you are paying for a peak rate.
30.
by maxhou 12y ago
> As a cable subscriber, I expect that when paying for N Mbps of bandwidth, I'm entitled to N Mbps of bandwidth of the content of my choosing 100% of the time ? not going to happen So let's say I'm an ISP and I bring a fib

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