d013a19fe2
Stefan Eissing
2026-08-27
Subject
multi: xfer table initial size and growth
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lib/multi.c+11 -18
| @@ -49,7 +49,7 @@ | |
| #include "bufref.h" | |
| /* initial multi->xfers table size for a full multi */ | |
| - | #define CURL_XFER_TABLE_SIZE 512 |
| + | #define CURL_XFER_TABLE_SIZE 128 |
| /* CURL_SOCKET_HASH_TABLE_SIZE should be a prime number. Increasing it from 97 | |
| to 911 takes on a 32-bit machine 4 x 804 = 3211 more bytes. Still, every | |
| @@ -423,27 +423,20 @@ static CURLMcode multi_xfers_add(struct Curl_multi *multi, | |
| if(capacity < max_capacity) { | |
| /* We want `multi->xfers` to have "sufficient" free rows, so that we do | |
| * not have to reuse the `mid` from a removed easy right away. | |
| - | * Since uint_tbl and uint_bset are memory efficient, |
| - | * regard less than 25% free as insufficient. |
| - | * (for low capacities, e.g. multi_easy, 4 or less). */ |
| + | * Check if an 8th of the capacity is still free */ |
| uint32_t used = Curl_uint32_tbl_count(&multi->xfers); | |
| uint32_t unused = capacity - used; | |
| - | uint32_t min_unused = CURLMAX(capacity >> 2, 4); |
| - | if(unused <= min_unused) { |
| + | uint32_t min_unused = CURLMAX(capacity >> 3, 4); |
| + | if(unused < min_unused) { |
| + | /* Grow by 50% of current capacity, in range of [128, 2048], |
| + | * which means the table grows max by 16kb on 64-bit arch. */ |
| + | uint32_t growth = CURLMIN(CURLMAX(capacity >> 1, 128), 2048); |
| /* Make sure the uint arithmetic here works on the corner | |
| * cases where we are close to max_capacity or UINT_MAX */ | |
| - | if((min_unused >= max_capacity) || |
| - | ((max_capacity - min_unused) <= capacity) || |
| - | ((UINT_MAX - min_unused - 63) <= capacity)) { |
| - | new_size = max_capacity; /* can not be larger than this */ |
| - | } |
| - | else { |
| - | /* make it a 64 multiple, since our bitsets grow by that and |
| - | * small (easy_multi) grows to at least 64 on first resize. */ |
| - | new_size = (((used + min_unused) + 63) / 64) * 64; |
| - | if(new_size < 256) /* don't be too shy about it */ |
| - | new_size = 256; |
| - | } |
| + | if((max_capacity - growth) <= capacity) |
| + | new_size = max_capacity; |
| + | else |
| + | new_size = capacity + growth; |
| } | |
| } | |