From 16f7018af1f278a9f0cc368e224258860ea4cb8c Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Thu, 6 Dec 2018 23:26:24 +0000 Subject: deduplicate strings VM-wide in Ruby 2.5+ String#-@ deduplicates strings starting with Ruby 2.5.0 Hash#[]= deduplicates strings starting in Ruby 2.6.0-rc1 This allows us to save a small amount of memory by sharing objects with other parts of the stack (e.g. Rack). --- ext/unicorn_http/common_field_optimization.h | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) (limited to 'ext/unicorn_http/common_field_optimization.h') diff --git a/ext/unicorn_http/common_field_optimization.h b/ext/unicorn_http/common_field_optimization.h index 251e734..4b9f062 100644 --- a/ext/unicorn_http/common_field_optimization.h +++ b/ext/unicorn_http/common_field_optimization.h @@ -58,6 +58,23 @@ static struct common_field common_http_fields[] = { #define HTTP_PREFIX "HTTP_" #define HTTP_PREFIX_LEN (sizeof(HTTP_PREFIX) - 1) +static ID id_uminus; + +/* this dedupes under Ruby 2.5+ (December 2017) */ +static VALUE str_dd_freeze(VALUE str) +{ + if (STR_UMINUS_DEDUPE) + return rb_funcall(str, id_uminus, 0); + + /* freeze,since it speeds up older MRI slightly */ + OBJ_FREEZE(str); + return str; +} + +static VALUE str_new_dd_freeze(const char *ptr, long len) +{ + return str_dd_freeze(rb_str_new(ptr, len)); +} /* this function is not performance-critical, called only at load time */ static void init_common_fields(VALUE mark_ary) @@ -65,18 +82,19 @@ static void init_common_fields(VALUE mark_ary) int i; struct common_field *cf = common_http_fields; char tmp[64]; + + id_uminus = rb_intern("-@"); memcpy(tmp, HTTP_PREFIX, HTTP_PREFIX_LEN); for(i = ARRAY_SIZE(common_http_fields); --i >= 0; cf++) { /* Rack doesn't like certain headers prefixed with "HTTP_" */ if (!strcmp("CONTENT_LENGTH", cf->name) || !strcmp("CONTENT_TYPE", cf->name)) { - cf->value = rb_str_new(cf->name, cf->len); + cf->value = str_new_dd_freeze(cf->name, cf->len); } else { memcpy(tmp + HTTP_PREFIX_LEN, cf->name, cf->len + 1); - cf->value = rb_str_new(tmp, HTTP_PREFIX_LEN + cf->len); + cf->value = str_new_dd_freeze(tmp, HTTP_PREFIX_LEN + cf->len); } - cf->value = rb_obj_freeze(cf->value); rb_ary_push(mark_ary, cf->value); } } @@ -105,7 +123,7 @@ static VALUE uncommon_field(const char *field, size_t flen) memcpy(RSTRING_PTR(f) + HTTP_PREFIX_LEN, field, flen); assert(*(RSTRING_PTR(f) + RSTRING_LEN(f)) == '\0' && "string didn't end with \\0"); /* paranoia */ - return rb_obj_freeze(f); + return HASH_ASET_DEDUPE ? f : str_dd_freeze(f); } #endif /* common_field_optimization_h */ -- cgit v1.2.3-24-ge0c7