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Optimize ObjectId#generate: cache the MD5 of the host name and generate counters in C instead of Ruby.

This commit is contained in:
Hongli Lai (Phusion) 2010-09-13 23:07:04 +02:00 committed by Kyle Banker
parent b474b29d35
commit bfa4926e1d
1 changed files with 26 additions and 9 deletions
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35
ext/cbson/cbson.c
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@ -183,6 +183,9 @@ static void write_utf8(buffer_t buffer, VALUE string, char check_null) {
static char zero = 0;
static char one = 1;
static char hostname_digest[17];
static unsigned int object_id_inc = 0;
static int cmp_char(const void* a, const void* b) {
return *(char*)a - *(char*)b;
}
@ -886,8 +889,7 @@ static VALUE fast_pack(VALUE self)
static VALUE objectid_generate(VALUE self)
{
VALUE oid, digest;
char hostname[MAX_HOSTNAME_LENGTH];
VALUE oid;
unsigned char oid_bytes[12];
unsigned long t, inc;
unsigned short pid;
@ -896,16 +898,22 @@ static VALUE objectid_generate(VALUE self)
t = htonl(time(NULL));
MEMCPY(&oid_bytes, &t, unsigned char, 4);
if (gethostname(hostname, MAX_HOSTNAME_LENGTH) != 0) {
rb_raise(rb_eRuntimeError, "failed to get hostname");
}
digest = rb_funcall(DigestMD5, rb_intern("digest"), 1, rb_str_new2(hostname));
MEMCPY(&oid_bytes[4], RSTRING_PTR(digest), unsigned char, 3);
MEMCPY(&oid_bytes[4], hostname_digest, unsigned char, 3);
pid = htons(getpid());
MEMCPY(&oid_bytes[7], &pid, unsigned char, 2);
inc = htonl(FIX2ULONG(rb_funcall(self, rb_intern("get_inc"), 0)));
/* No need to synchronize modification of this counter between threads;
* MRI global interpreter lock guarantees serializaility.
*
* Compiler should optimize out impossible branch.
*/
if (sizeof(unsigned int) == 4) {
object_id_inc++;
} else {
object_id_inc = (object_id_inc + 1) % 0xFFFFFF;
}
inc = htonl(object_id_inc);
MEMCPY(&oid_bytes[9], ((unsigned char*)&inc + 1), unsigned char, 3);
oid = rb_ary_new2(12);
@ -917,7 +925,8 @@ static VALUE objectid_generate(VALUE self)
void Init_cbson() {
VALUE bson, CBson, Digest, ext_version;
VALUE bson, CBson, Digest, ext_version, digest;
static char hostname[MAX_HOSTNAME_LENGTH];
element_assignment_method = rb_intern("[]=");
unpack_method = rb_intern("unpack");
@ -962,4 +971,12 @@ void Init_cbson() {
rb_define_method(ObjectId, "generate", objectid_generate, 0);
rb_define_method(rb_cArray, "fast_pack", fast_pack, 0);
if (gethostname(hostname, MAX_HOSTNAME_LENGTH) != 0) {
rb_raise(rb_eRuntimeError, "failed to get hostname");
}
digest = rb_funcall(DigestMD5, rb_intern("digest"), 1,
rb_str_new2(hostname));
memcpy(hostname_digest, RSTRING_PTR(digest), 16);
hostname_digest[16] = '\0';
}