EV::Future

High-performance async control flow for Perl's EV event loop, implemented in XS.

Functions

• parallel(\@tasks, \&final_cb [, $unsafe]) - run all tasks concurrently
• parallel_limit(\@tasks, $limit, \&final_cb [, $unsafe]) - concurrent with concurrency limit
• series(\@tasks, \&final_cb [, $unsafe]) - run tasks sequentially
• race(\@tasks, \&final_cb [, $unsafe]) - first task to finish wins; its args go to final_cb
• parallel_map(\@items, \&worker, \&final_cb [, $unsafe]) - worker per item, concurrently
• parallel_map_limit(\@items, \&worker, $limit, \&final_cb [, $unsafe]) - worker per item, with a limit
• series_map(\@items, \&worker, \&final_cb [, $unsafe]) - worker per item, sequentially

Called in non-void context, each returns a handle supporting cancel, pending and active.

Install

perl Makefile.PL && make && make test

Requires Perl 5.14+, EV 4.37+, and a C compiler.

Benchmarks

1000 sync tasks x 5000 iterations (bench/comparison.pl; race is not covered by that script, so it has no row here). Measured with EV 4.37, AnyEvent 7.17, Future::XS 0.15, Promise::XS 0.21 and Future::Utils 0.52:

| | parallel | parallel_limit(10) | series | |---|---:|---:|---:| | EV::Future (unsafe) | 9,259 | 7,692 | 7,692 | | EV::Future (safe) | 4,098 | 4,032 | 3,968 | | AnyEvent cv | 1,563 | - | 4,717 | | Future::XS | 1,563 | 624 | 1,241 | | Promise::XS | 1,323 | - | 1,157 |

Safe mode adds per-task double-call protection and G_EVAL. Unsafe mode skips both, roughly doubling throughput.

Examples

The eg/ directory has runnable examples that need nothing but EV:

• map_limit.pl - a worker per item with a concurrency limit
• series_map_pipeline.pl - a sequential pipeline that stops at the first failure
• cancel_progress.pl - the handle: pending, active and early cancel
• race_timeout.pl - racing work against a timeout, and tearing the loser down

Alongside them, curl_parallel.pl, redis_parallel.pl and etcd_series.pl show real clients (AnyEvent::YACurl, EV::Hiredis, EV::Etcd), and need those modules and a reachable service.