Performance degradation of Buffer allocation in NodeJS v24

Version

v24.13.0

Platform

Linux ubuntu24 6.14.0-37-generic #37~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Nov 20 10:25:38 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

No response

What steps will reproduce the bug?

console.log(process.version);
let table = [], count = 1e6;
for (let chunk_size of [10, 20, 50, 100, 200].map(v=>v*1024))
{
    let ts = Date.now();
    for (let i = 0; i<count; i++)
        Buffer.allocUnsafe(chunk_size);
    let te = Date.now();
    table.push({chunk_size, ms: te-ts});
}
console.table(table, ['chunk_size', 'ms']);

How often does it reproduce? Is there a required condition?

Every time

What is the expected behavior? Why is that the expected behavior?

Buffer allocation in NodeJS v24 should be same or better than in v20.

What do you see instead?

Degradation depended on chunk size:

v20.12.1
┌─────────┬────────────┬──────┐
│ (index) │ chunk_size │ ms   │
├─────────┼────────────┼──────┤
│ 0       │ 10240      │ 1044 │
│ 1       │ 20480      │ 1110 │
│ 2       │ 51200      │ 1230 │
│ 3       │ 102400     │ 1339 │
│ 4       │ 204800     │ 1969 │
└─────────┴────────────┴──────┘


v24.13.0
┌─────────┬────────────┬──────┐
│ (index) │ chunk_size │ ms   │
├─────────┼────────────┼──────┤
│ 0       │ 10240      │ 996  │
│ 1       │ 20480      │ 1223 │
│ 2       │ 51200      │ 1387 │
│ 3       │ 102400     │ 2077 │
│ 4       │ 204800     │ 3349 │
└─────────┴────────────┴──────┘

Additional information

No response

首先在所述 Linux 环境中运行随附的 Buffer.allocUnsafe 基准测试，分别使用 Node.js v20.12.1 和 v24.13.0，然后检查 Buffer 分配路径是否有影响较大 chunk 的变更。完成的标准是解释清楚该回归问题，并通过可复现的基准测试或测试演示相关行为及任何修复。