sync.Pool survives one GC, not two
A pool holding 100 objects lost none across one collection and all 100 across two. Here is the victim cache, and what it costs at 122,000 ops per millisecond.
Writing
Long-form notes on the Go runtime, concurrency, performance and the systems underneath.
Escape analysis is not a rule of thumb
The compiler said "does not escape" and the benchmark reported 104 KiB per operation. Both were right. What -gcflags=-m actually tells you.
What the Go scheduler does when your goroutine blocks
A blocking syscall costs an OS thread. A blocking network read costs nothing. Measured with 200 goroutines, GOMAXPROCS=2 and a thread count.