Notes from a real debugging session chasing a register-corruption bug in inline-asm coroutine scheduling on Apple Silicon. The bug itself isn't the point — these are the tool habits and mental models that let me actually find it.
otool -tvV dumps Mach-O disassembly with symbols and PC
| Promises in Javascript trade one problem (callback nesting) for a worse one (silent failures). | |
| With callbacks you always knew when something broke. With swallowed errors, you have to add debug statements | |
| until you've tracked down where the error got swallowed. | |
| 10 seconds vs. 10 minutes |
Installing dependencies
sudo apt-get install build-essential clang libdbus-1-dev libgtk2.0-dev \
libnotify-dev libgnome-keyring-dev libgconf2-dev \
libasound2-dev libcap-dev libcups2-dev libxtst-dev \
gcc-multilib g++-multilib \
libgtk2.0-0 libgconf-2-4 \
libasound2 libxtst6 libxss1 libnss3 xvfb \
javascript got one thing right with callbacks. that got thrown out with promises.
=>async await is not a coroutine
| // take a number 6 -> binary | |
| console.log(convert(10)) | |
| function convert(n){ | |
| let remainder = [] | |
| while (n){ | |
| remainder.push(n % 2) | |
| n = parseInt(n/2) // keep dividing it | |
| } |
| console.log(primesum(2000000)) | |
| function primesum(m){ | |
| let ret = 7, i = 1 //(ret=7) prepopulate 2 and 5, dropped by optimization | |
| while (i++ < m) { | |
| if (isprime(i)) |
| #include <setjmp.h> | |
| #include <signal.h> | |
| #include <stdio.h> | |
| #include <string.h> | |
| static void do_segv() { | |
| /* lets do some stuff that would segfault on any system */ | |
| int *segv; | |
| segv = 0; /* malloc(a_huge_amount); */ |
Cian Johnston, July 2017
A couple of weeks ago, I decided I should put my gaming rig to work crypto mining. I did not expect to make any significant profit on this, it was more of a fun project to set up. However, there were a large number of tutorials and guides already out there, and many were more than a year out of date.
This guide assumes the reader already has a crypto wallet set up, is comfortable with Linux and the command line, and knows how to use Google if they run into problems.
The end result is an Ubuntu 16.04 LTS headless server running CUDA ethminer via systemd.
I'm in no case responsible for fried hardware, erased software or burning down houses. Make sure your miners are always well cooled.
Though you can easily mix nVidia and AMD in the same rig with Linux, it's recommended to use a different thread for each platform so a Driver crash doesn't bring the whole rig down. It should be noted however, that some mining software have trouble when both architecture are found on the same rig.
| miner@rig3:~$ /opt/rocm/bin/rocm-smi -P | |
| ==================== ROCm System Management Interface ==================== | |
| ================================================================================ | |
| GPU[1] : Cannot get GPU power Consumption: Average GPU Power not supported | |
| GPU[2] : Cannot get GPU power Consumption: Average GPU Power not supported | |
| GPU[0] : Cannot get GPU power Consumption: Average GPU Power not supported | |
| ================================================================================ | |
| ==================== End of ROCm SMI Log ==================== |