reza_n

9 ms·

31.
by reza_n 9y ago
Most variables are registers, so it would have no effect on cache since there is no memory used to store the data. Only if that variable is pushed onto the stack/heap would it then consume cache. However, the size of the stack is much
32.
by reza_n 9y ago
Lenovo Thinkpad X1 carbon. I have a 2nd gen I bought in 2014 and its been rock solid for the last 4 years. I have been running Ubuntu since day 1 and have had 0 issues. I travel with this laptop daily, so its very mobile. Lightweight, quiet
33.
Announcing Varnish Cash Blockchain(info.varnish-software.com)
6 points by reza_n 9y ago|0 comments
34.
by reza_n 9y ago
Constructs like closures come at a cost. Function call abstraction and locality means hardware cannot easily prefetch, instruction cache misses, data cache misses, memory copying, basically, a lot of the slowness you see in dynamic language
35.
by reza_n 9y ago
I would prefer to keep this public just because its sometimes a good idea to have a record of things like this. I feel this wont be the last time this rears its ugly head. > you've demonstrated to the world in this thread you have n
36.
by reza_n 9y ago
> Someone in the varnish org should be able to do a competitive analysis of Varnish, ATS, and Nginx in a couple days that would be enlightening and prudent use of time to guide your product development. Really? I would say most of us are
37.
by reza_n 9y ago
Another huge load of BS. What is your goal here? > epoll/kqueue Here is the implementation from 2.1, back maybe around 10 years ago: https://github.com/varnishcache/varnish-cache/blob/2.1/bin&#x2F
38.
by reza_n 9y ago
This is another misinformed rant. > Varnish I/O model is ignorant of TLB flushing, instruction cache, VM hints like madvise(2), and the overhead (and downright difficult job) of an OS scheduler. TLB flushing is a hardware problem, n
39.
by reza_n 9y ago
> Doing a thread per connection is about the worst conceivable design for web acceleration. A better statement here would be connections are serviced by a pool of workers. Event polling is used. A single worker can and does process ten
40.
by reza_n 9y ago
> 3. New news. NY Times topped $1 billion in subscription revenue last year. Quite a feat and definitely an indication that money is to be made in digital news. https://www.nytimes.com/2018/02/08/business&#
41.
by reza_n 9y ago
> But it certainly can change the condition in the assertion so that it won't fire on overflow. Once again, why would a compiler do that? To satisfy the Rust community's desire to spread FUD throughout the C community? (sorry t
42.
by reza_n 9y ago
I can see the point you are trying to make, but in this context, it doesn't work. Lets start at line 20: vec.capacity = 0; Next, line 26: int new_capacity = vec->capacity * 2; So we get new_capacity = 0 * 2, so new_cap
43.
by reza_n 9y ago
How does a compiler know that signed overflow will happen in the above snippet? Couldn't all integer math result in overflow? If so, how does the compiler ever know what to do? I do not think its plausible that the compiler is emitting
44.
by reza_n 9y ago
Nothing in the snippet is undefined. The assert simply enforces the size always increases. Not sure I understand why you think the assert() gets removed. Is this documented somewhere? Hint: vec->capacity could be 0
45.
by reza_n 9y ago
Overflow is a runtime behavior, not a compile time behavior. How a type overflows is dependent on the CPU, not software.
46.
by reza_n 9y ago
I would argue the opposite, assert() statements are the best way to write defensive and secure C. There might have been a time when people commonly compiled out assert() statements from binaries, but that is only OK if the software was desi
47.
by reza_n 9y ago
Very valid point. The code for that: int new_capacity = vec->capacity * 2; assert(new_capacity > vec->capacity);
48.
by reza_n 9y ago
As another poster pointed out, if I run this via valgrind (after fixing the first error): > valgrind ./a.out ==4871== Invalid write of size 4 ==4871== at 0x40073A: vec_push (test.c:40) ==4871== Invalid write of size 4
49.
by reza_n 9y ago
Not exactly the best example. If I take this code (test.c) and try to compile it: > gcc test.c I get an error: test.c:21:3: warning: function returns address of local variable [-Wreturn-local-addr] return &vec;
50.
by reza_n 9y ago
Varnish Software | Software Engineer | London, UK Varnish Software is the company behind Varnish Cache. Varnish Software works with top global enterprises helping them use Varnish Cache to increase web performance and to build private CDNs,
51.
Varnish Cache Meltdown Performance(info.varnish-software.com)
16 points by reza_n 9y ago|2 comments
52.
by reza_n 9y ago
See if you can spot the sub 4s route: https://youtu.be/IngelKjmecg
53.
by reza_n 9y ago
A lot of the examples brought up are innovations in communication, not AI. Phones, social media, and search are communication platforms. Just like books, newspapers, telegraph, telephones, internet, they enable communication, interaction, i
54.
by reza_n 9y ago
Varnish Software | Software Engineer | NYC, London Varnish Software is the company behind Varnish Cache, a widely recognized open source HTTP proxy that significantly enhances web performance and enables digital content delivery. Varnish Ca
55.
by reza_n 9y ago
Not to mention that there was a race condition in the implementation which would cause random memory corruption under high memory load. Varnish Cache would consistently hit this. Recently fixed: https://access.redhat.com/doc
56.
by reza_n 9y ago
The get operation provides parts of the key used to decrypt the data you are after. No key, no data. Edit: the key comes from the user, its not stored anywhere on a server. The key can optionally never leave the user's device.
57.
by reza_n 9y ago
We have an encryption scheme where all user data has its own unique user based key. So compromising 1 user key only lets you have access to that user data and that key has access to nothing else. Your statement is correct when you said that
58.
by reza_n 9y ago
It is well understood that all variables need to be initialized. Most compilers consider uninitialized variables an error. So I would say someone running into this and possibly other UB scenarios is just a case of writing bad code.
59.
by reza_n 9y ago
Please explain how that is UB?
60.
by reza_n 9y ago
Do you have any examples of this uncertainty? I hear this argument a lot, but have a hard time understanding why this seems to be a common grievance. I've been writing C for years and never once did I hit a scenario of dealing with und

More ›