I couldn't find much information about what the fastest way to write to a file is using Rust so I tried testing a few methods I've seen or variations I could think of. The context I was considering when looking for the fastest write method was a server that accepts as many incomming network connections as possible, receives a short message, and writes it directly to disk in a sequential file. This means there would be many threads all trying to write to the same file at the same time.
Tests:
- Normal for loop using tokio's
File/write - Spawning tasks using an
Arc<Mutex<File>>to synchronizing writing - Spawning tasks writing to a MPSC channel with a single separate thread writing
- Spawning tasks writing to an unbounded flume channel with a single separate write thread using BufWriter
- Spawning tasks writing to an unbounded flume channel with 10 write threads consuming
- Spawning tasks writing to an unbounded flume channel with a rendezvous channel
Each of these tests run some number of writes that contain a random payload between a min and max size.
I wouldn't rely too much on these numbers other than to say any synchronization methods seem to have a similar impact, except for buffered writing in a single consumer thread.
===== Running test rusty_writes::flume_mpsc_buffered_writer_test::FlumeMpscBufferedWriterTest (1000000 writes of size 300..2000) =====
Mean: 626.31 ms (626311420.51 ns)
Median: 789.22 ms (789216459.00 ns)
P90: 869.30 ms (869299584.00 ns)
Writes/s: 397396.37
Total Bytes: 1149.17 MB
Total Writes: 1000000
Total Time: 2516.38 ms
Completed test for rusty_writes::flume_mpsc_buffered_writer_test::FlumeMpscBufferedWriterTest in 2.52 s (2516.39 ms)
===== Running test rusty_writes::sync_io_test::SyncIoTest (1000000 writes of size 300..2000) =====
Mean: 0.01 ms (6843.42 ns)
Median: 0.01 ms (6208.00 ns)
P90: 0.01 ms (8750.00 ns)
Writes/s: 140792.95
Total Bytes: 1149.33 MB
Total Writes: 1000000
Total Time: 7102.63 ms
Completed test for rusty_writes::sync_io_test::SyncIoTest in 7.10 s (7102.64 ms)
===== Running test rusty_writes::arc_mutex_test::ArcMutexTest (1000000 writes of size 300..2000) =====
Mean: 5179.73 ms (5179727105.90 ns)
Median: 5224.68 ms (5224681959.00 ns)
P90: 8757.26 ms (8757262000.00 ns)
Writes/s: 96453.55
Total Bytes: 1149.67 MB
Total Writes: 1000000
Total Time: 10367.68 ms
Completed test for rusty_writes::arc_mutex_test::ArcMutexTest in 10.37 s (10367.69 ms)
===== Running test rusty_writes::mpsc_single_writer_test::MpscSingleWriterTest (1000000 writes of size 300..2000) =====
Mean: 4500.68 ms (4500678987.50 ns)
Median: 4560.64 ms (4560635625.00 ns)
P90: 7552.71 ms (7552711500.00 ns)
Writes/s: 94584.88
Total Bytes: 1150.04 MB
Total Writes: 1000000
Total Time: 10572.51 ms
Completed test for rusty_writes::mpsc_single_writer_test::MpscSingleWriterTest in 10.57 s (10572.52 ms)
File size 1149162905 matches 1149162905 bytes written
===== Running test rusty_writes::flume_mpmc_test::FlumeMpmcTest (1000000 writes of size 300..2000) =====
Mean: 0.12 ms (120934.44 ns)
Median: 0.11 ms (111375.00 ns)
P90: 0.19 ms (187750.00 ns)
Writes/s: 81573.03
Total Bytes: 1149.16 MB
Total Writes: 1000000
Total Time: 12258.95 ms
Completed test for rusty_writes::flume_mpmc_test::FlumeMpmcTest in 12.26 s (12258.96 ms)