Commit d3ef412
buffer: increase Buffer.poolSize default to 64 KiB
The 8 KiB default has been unchanged since 2015. With the threshold
check `size < (Buffer.poolSize >>> 1)`, this means allocations of 4 KiB
or larger bypass the pool entirely — including 4 KiB itself, a common
page and HTTP-frame size.
Raising the default to 64 KiB extends pool coverage to ~32 KiB
allocations, capturing common sizes used by HTTP parsers, stream
chunks, and small file reads.
Throughput improvements on workers-k=8 fs.readFileSync benchmarks
(Linux/glibc) at the affected sizes, with no regressions elsewhere:
file size | 8 KiB pool | 64 KiB pool | delta
-----------+--------------+---------------+-------
4 KiB | 326k ops/s | 360k ops/s | +10%
8 KiB | 202k ops/s | 254k ops/s | +26%
16 KiB | 148k ops/s | 181k ops/s | +23%
64 KiB | 86k ops/s | 87k ops/s | ~
1 MiB | 12k ops/s | 13k ops/s | ~
Cost: +56 KiB RSS per realm at startup.
Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: #63597
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: LiviaMedeiros <livia@cirno.name>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Ethan Arrowood <ethan@arrowood.dev>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>1 parent f954ab3 commit d3ef412
2 files changed
Lines changed: 7 additions & 3 deletions
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -881,7 +881,7 @@ _may contain sensitive data_. Use [`buf.fill(0)`][`buf.fill()`] to initialize | |||
| 881 | 881 | such `Buffer` instances with zeroes. | |
| 882 | 882 | ||
| 883 | 883 | When using [`Buffer.allocUnsafe()`][] to allocate new `Buffer` instances, | |
| 884 | - allocations less than `Buffer.poolSize >>> 1` (4KiB when default poolSize is used) are sliced | ||
| 884 | + allocations less than `Buffer.poolSize >>> 1` (32KiB when default poolSize is used) are sliced | ||
| 885 | 885 | from a single pre-allocated `Buffer`. This allows applications to avoid the | |
| 886 | 886 | garbage collection overhead of creating many individually allocated `Buffer` | |
| 887 | 887 | instances. This approach improves both performance and memory usage by | |
@@ -1513,9 +1513,13 @@ console.log(Buffer.isEncoding('')); | |||
| 1513 | 1513 | ||
| 1514 | 1514 | <!-- YAML | |
| 1515 | 1515 | added: v0.11.3 | |
| 1516 | + changes: | ||
| 1517 | + - version: REPLACEME | ||
| 1518 | + pr-url: https://github.com/nodejs/node/pull/63597 | ||
| 1519 | + description: Default raised from 8192 to 65536. | ||
| 1516 | 1520 | --> | |
| 1517 | 1521 | ||
| 1518 | - * Type: {integer} **Default:** `8192` | ||
| 1522 | + * Type: {integer} **Default:** `65536` | ||
| 1519 | 1523 | ||
| 1520 | 1524 | This is the size (in bytes) of pre-allocated internal `Buffer` instances used | |
| 1521 | 1525 | for pooling. This value may be modified. | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -171,7 +171,7 @@ const constants = ObjectDefineProperties({}, { | |||
| 171 | 171 | }, | |
| 172 | 172 | }); | |
| 173 | 173 | ||
| 174 | - Buffer.poolSize = 8 * 1024; | ||
| 174 | + Buffer.poolSize = 64 * 1024; | ||
| 175 | 175 | let poolSize, poolOffset, allocPool, allocBuffer; | |
| 176 | 176 | ||
| 177 | 177 | function createPool() { | |
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