Thanh Le lenguyenthanh

Understanding Comparative Benchmarks

I'm going to do something that I don't normally do, which is to say I'm going to talk about comparative benchmarks. In general, I try to confine performance discussion to absolute metrics as much as possible, or comparisons to other well-defined neutral reference points. This is precisely why Cats Effect's readme mentions a comparison to a fixed thread pool, rather doing comparisons with other asynchronous runtimes like Akka or ZIO. Comparisons in general devolve very quickly into emotional marketing.

But, just once, today we're going to talk about the emotional marketing. In particular, we're going to look at Cats Effect 3 and ZIO 2. Now, for context, as of this writing ZIO 2 has released their first milestone; they have not released a final 2.0 version. This implies straight off the bat that we're comparing apples to oranges a bit, since Cats Effect 3 has been out and in production for months. However, there has been a post going around which cites various compar

A Study in Multi-Point Deadlocks

Deadlocks are extremely difficult to reason about sometimes. We are used to thinking about them in terms of contention over shared resources, with the pair of exclusive locks being a good and relatively canonical example of this phenomenon. However, sometimes you can find yourself in deadlock scenarios which are caused not so much by an improper sequencing of exclusivity, but rather by insufficient buffer capacity!

These kinds of scenarios are a lot rarer and much more difficult to diagnose and describe, which is why I found this particular puzzle so incredibly fascinating. The following is a screenshot from Cities Skylines (I added textual markers and arrows to make things easier to follow). All vehicles pictured are stationary and unable to move, indefinitely:

Do you see the deadlock? It took me a bit to understand it, but this situation can and does arise in software resource contention where it is dramatically harder to conc

Greasing the Skids: Building Remote Teams

In the wake of the virus that-must-not-be-named (which most people misname anyway), it seems like everyone and their cat has posted some sort of opinion or how-to on making remote work, work. This is a good thing! Working remotely, particularly full-time, is hard! I've done it for my entire career (aside from an odd 14 month office period in the middle that we shall not speak of), but more relevantly, for the past two years I've been responsible for building, managing, and enabling an entirely remote team, distributed across nine timezones. Remote teams don't just happen by installing Slack and telling everyone to work on their couch: they require a lot of effort to do correctly and efficiently. But, done right, it can be a massive multiplier on your team efficiency and flexibility.

Here's how we do it. I'm going to attempt to structure this post more towards management than engineering, and so I apologize in advance if I assume terminology or knowledge which

Program Analysis Resources

(draft; work in progress)

Haskell in Production: Adventures in Blockchain Building

	import arrow.continuations.Effect
	import arrow.continuations.generic.DelimitedScope
	import arrow.core.Either
	import arrow.core.right
	import com.squareup.sqldelight.TransactionWithReturn
	import kotlin.coroutines.RestrictsSuspension

	/**
	* Either-Syntax for SqlDelight transactions.
	*

	import arrow.core.*
	import memeid.UUID

	data class User(val email: String, val name: String) {
	companion object
	}

	data class ProcessedUser(val id: UUID, val email: String, val name: String) {
	companion object
	}

	-----------------------------------------------------------
	-- HOW TO ASK FOR HELP AND AVOID ARGUMENTS.
	--
	-- When we want to use an externally-provided package (such as logging,
	-- database connections, etc) in our work code, it might require some initial
	-- config that we traditionally store in our environment.
	--
	-- We might even require something like a database connection or file handler
	-- /throughout/ the lifetime of the code, in order to make queries or similar.
	--


	import android.app.Activity
	import android.app.Dialog
	import android.content.Context
	import android.view.View
	import androidx.fragment.app.Fragment
	import androidx.test.platform.app.InstrumentationRegistry
	import androidx.test.platform.app.InstrumentationRegistry.getInstrumentation
	import com.facebook.testing.screenshot.Screenshot
	import com.facebook.testing.screenshot.ViewHelpers


	final case class ZIO[-R, +E, +A](run: R => Either[E, A]) {
	final def map[B](f: A => B): ZIO[R, E, B] =
	ZIO(r => run(r).map(f))

	final def flatMap[R1 <: R, E1 >: E, B](f: A => ZIO[R1, E1, B]): ZIO[R1, E1, B] =
	ZIO(r => run(r).flatMap(a => f(a).run(r)))

	final def provide(r: R): ZIO[Any, E, A] =
	ZIO(_ => run(r))