MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

pprett

"""
Benchmark sklearn's SGDClassifier on RCV1-ccat dataset.

So generate the input files see http://leon.bottou.org/projects/sgd .

Results
-------
ACC: 0.9479
AUC: 0.9476

P7h

-server
-Xms2048m
-Xmx2048m
-XX:NewSize=512m
-XX:MaxNewSize=512m
-XX:PermSize=512m
-XX:MaxPermSize=512m
-XX:+UseParNewGC
-XX:ParallelGCThreads=4
-XX:MaxTenuringThreshold=1

johnmyleswhite

# Generate (x, y) data with a sparse set of active predictors
# prob controls the frequency of predictors having zero effect
function simulate_date(n::Integer, p::Integer, prob::Real)
  x = randn(n, p)
	beta = randn(p)
	for j in 1:p
		if rand() < prob
			beta[j] = 0.0
		end
	end

jcs

Update (2019-05-06): The Broadcom wireless card in the MacBook Pro works and can be crammed into the Air.

Update (2015-12-04): This document used to be very lengthy as there were many manual steps required to get OpenBSD and Mac OS X working together through Boot Camp Assistant (BCA), which created a hybrid MBR and enabled a legacy BIOS emulation mode which older versions of Windows (and OpenBSD) required. Newer Macbooks stopped supporting older versions of Windows through BCA and now only support Windows 10 since it uses GPT and UEFI. However, now that newer versions of OpenBSD support GPT and UEFI, Boot Camp Assistant is no longer needed at all to boot OpenBSD.

macOS FileVault encryption and OpenBSD encrypted softraid on a Macbook Air/Pro

OpenBSD works pretty well on at least the Mid-2011 Macbook Air (A1370, SandyBridge) and Mid-2013 Macbook Air (Haswell). The new KMS code in 5.4 brings up the MBA's eDP display in 1366x768 with backlight

adamwiggins

Make it real

Ideas are cheap. Make a prototype, sketch a CLI session, draw a wireframe. Discuss around concrete examples, not hand-waving abstractions. Don't say you did something, provide a URL that proves it.

Ship it

Nothing is real until it's being used by a real user. This doesn't mean you make a prototype in the morning and blog about it in the evening. It means you find one person you believe your product will help and try to get them to use it.

Do it with style

pozorvlak

Here's where I understand the state of the art to be:

• In this INRIA tech report, Shapiro, Preguiça, Baquero and Zawirski (SPBZ) prove, amongst other things, that a sufficient condition for CRDTs to achieve eventual consistency on networks which may reorder and duplicate packets (which I'll call flaky networks, henceforth) is that
  1. the underlying datatype forms a semilattice,
  2. messages are full states,
  3. incoming messages are combined with the node's current state using the least-upper-bound operation in the semilattice.
• It's possible to relax condition 2 and still achieve eventual consistency over flaky networks by fragmenting the state into independent parts and transmitting updates to each part separately. For instance, in the G-Set CRDT (an add-only bitset) one can transmit only the index of the element to be added.
• In [these slides from a talk at Dagstuhl](http://www.dagstuhl.de/mat/Files/13/13081/13081.BaqueroCarlos.Sl

chanks

Turning PostgreSQL into a queue serving 10,000 jobs per second

RDBMS-based job queues have been criticized recently for being unable to handle heavy loads. And they deserve it, to some extent, because the queries used to safely lock a job have been pretty hairy. SELECT FOR UPDATE followed by an UPDATE works fine at first, but then you add more workers, and each is trying to SELECT FOR UPDATE the same row (and maybe throwing NOWAIT in there, then catching the errors and retrying), and things slow down.

On top of that, they have to actually update the row to mark it as locked, so the rest of your workers are sitting there waiting while one of them propagates its lock to disk (and the disks of however many servers you're replicating to). QueueClassic got some mileage out of the novel idea of randomly picking a row near the front of the queue to lock, but I can't still seem to get more than an an extra few hundred jobs per second out of it under heavy load.

So, many developers have started going straight t

lavalamp

There are three easy to make mistakes in go. I present them here in the way they are often found in the wild, not in the way that is easiest to understand.

All three of these mistakes have been made in Kubernetes code, getting past code review at least once each that I know of.

1. Loop variables are scoped outside the loop.

What do these lines do? Make predictions and then scroll down.

func print(pi *int) { fmt.Println(*pi) }

jonhoo

Distributed Read-Write Mutex in Go

This project has moved to https://github.com/jonhoo/drwmutex so it can be imported into Go applications.