Standard library

velt/sync/epoch

API reference

Epoch-based reclamation, written in Velt on Atomic, ThreadLocal and Mutex: a way to drop a shared value that other threads may still be reading, once none can be. The compiler calls it for the values an Atomic of a shared value replaces, and opens a section around a function that loads one. For a walkthrough, read the guide.

import { collect } from "velt/sync/epoch";

Exports

collectMoves the epoch on if every thread in a section has seen the current one, then drops every value retired 2 epochs or more before, on every thread's list.droppedThe values dropped so far, on every thread (by collect, and by retire's own collects).outstandingThe values retired on every thread and not dropped yet.pendingThe values retired on this thread and not dropped yet.pinEnters a section: until the matching unpin(), no value retired from now on is dropped, and neither is one retired before that this thread can still reach.retireDrops value once no thread can still be reading it: every thread in a section now has left it.unpinLeaves the section the last pin() entered.

function

collect

#std/sync/epoch/reclaim.vlt:137

Re-exported from velt/sync/epoch/reclaim

function collect(): u64

Moves the epoch on if every thread in a section has seen the current one, then drops every value retired 2 epochs or more before, on every thread's list. Returns how many it dropped.

function

dropped

#std/sync/epoch/reclaim.vlt:151

Re-exported from velt/sync/epoch/reclaim

function dropped(): u64

The values dropped so far, on every thread (by collect, and by retire's own collects).

function

outstanding

#std/sync/epoch/reclaim.vlt:156

Re-exported from velt/sync/epoch/reclaim

function outstanding(): u64

The values retired on every thread and not dropped yet.

function

pending

#std/sync/epoch/reclaim.vlt:166

Re-exported from velt/sync/epoch/reclaim

function pending(): u64

The values retired on this thread and not dropped yet.

function

pin

#std/sync/epoch/reclaim.vlt:77

Re-exported from velt/sync/epoch/reclaim

function pin(): void

Enters a section: until the matching unpin(), no value retired from now on is dropped, and neither is one retired before that this thread can still reach. Sections nest.

function

retire

#std/sync/epoch/reclaim.vlt:109

Re-exported from velt/sync/epoch/reclaim

function retire<T>(value: shared<T>): void

Drops value once no thread can still be reading it: every thread in a section now has left it. Call it for a value just taken out of where other threads find it.

function

unpin

#std/sync/epoch/reclaim.vlt:94

Re-exported from velt/sync/epoch/reclaim

function unpin(): void

Leaves the section the last pin() entered.