123456789101112131415161718192021222324252627282930313233343536373839 |
- // Copyright (c) 2018 Shivaram Lingamneni
-
- package irc
-
- import (
- "runtime"
-
- "github.com/oragono/oragono/irc/utils"
- )
-
- // See #237 for context. Operations that might allocate large amounts of temporary
- // garbage, or temporarily tie up some other resource, may cause thrashing unless
- // their concurrency is artificially restricted. We use `chan bool` as a
- // (regrettably, unary-encoded) counting semaphore to enforce these restrictions.
-
- const (
- // this is a tradeoff between exploiting CPU-level parallelism (higher values better)
- // and not thrashing the allocator (lower values better). really this is all just
- // guesswork. oragono *can* make use of cores beyond this limit --- just not for
- // the protected operations.
- MaxServerSemaphoreCapacity = 32
- )
-
- // ServerSemaphores includes a named Semaphore corresponding to each concurrency-limited
- // sever operation.
- type ServerSemaphores struct {
- // each distinct operation MUST have its own semaphore;
- // methods that acquire a semaphore MUST NOT call methods that acquire another
- ClientDestroy utils.Semaphore
- }
-
- // Initialize initializes a set of server semaphores.
- func (serversem *ServerSemaphores) Initialize() {
- capacity := runtime.NumCPU()
- if capacity > MaxServerSemaphoreCapacity {
- capacity = MaxServerSemaphoreCapacity
- }
- serversem.ClientDestroy.Initialize(capacity)
- }
|