[Python-Dev] The untuned tunable parameter ARENA_SIZE (original) (raw)

INADA Naoki songofacandy at gmail.com
Fri Jun 2 07:56:31 EDT 2017

I would be curious of another test: use pymalloc for objects larger than 512 bytes. For example, allocate up to 4 KB?

Since current pool size is 4KB and there is pool_header in pool, we can't allocate 4KB block from pool. And if support 1KB block, only 3KB of 4KB can be actually used. I think 512 bytes / 4KB (1/8) is good ratio.

Do you mean increase pool size?

How about adding configure option like server-mode?

SMALL_REQUEST_THRESHOLD 1024 // 2x POOL_SIZE (161024) // 4x ARENA_SIZE (21024*1024) // 8x, and same to huge page size.

In the past, we already changed the maximum size from 256 to 512 to support most common Python objects on 64-bit platforms. Since Python objects contain many pointers: switching from 32 bit to 64 bit can double the size of the object in the worst case.

Make sense.

Naoki

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