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smush together two return values from C

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avoids a per-packet alloc

i will atone for my sins later

if only C let you return multiple values.
or Go let you pass in a pointer w/o it being on the heap.
This commit is contained in:
Josh Bleecher Snyder
2021-06-01 22:11:40 -07:00
parent bb78cf81b6
commit 56ba714e10
2 changed files with 15 additions and 11 deletions
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17
net/uring/io_uring.c
View File

@@ -20,7 +20,7 @@ typedef struct iovec go_iovec;
typedef struct sockaddr_in go_sockaddr_in;
// Wait for a completion to be available, fetch the data
static int receive_into(struct io_uring *ring, size_t *idxptr) {
static uint64_t receive_into(struct io_uring *ring) {
struct io_uring_cqe *cqe;
again:;
@@ -38,15 +38,18 @@ again:;
fprintf(stderr, "recvmsg failed: %d.\n", cqe->res);
return cqe->res;
}
*idxptr = (size_t)(io_uring_cqe_get_data(cqe));
if (*idxptr < 0) {
size_t idxptr = (size_t)(io_uring_cqe_get_data(cqe));
uint32_t idxptr32 = (uint32_t)(idxptr);
uint64_t idxptr64 = (uint64_t)(idxptr32);
uint64_t n = cqe->res;
uint32_t n32 = (uint32_t)n;
uint64_t n64 = (uint64_t)n;
io_uring_cqe_seen(ring, cqe);
if (idxptr < 0) {
fprintf(stderr, "received nop\n");
io_uring_cqe_seen(ring, cqe);
return -1;
}
int n = cqe->res;
io_uring_cqe_seen(ring, cqe);
return n;
return (n64 << 32) | idxptr64;
}
static uint32_t ip(struct sockaddr_in *sa) {

9
net/uring/io_uring_linux.go
View File

@@ -56,7 +56,7 @@ func NewUDPConn(conn *net.UDPConn) (*UDPConn, error) {
}
r := new(C.go_uring)
const queue_depth = 8 // TODO: What value to use here?
const queue_depth = 16 // TODO: What value to use here?
C.io_uring_queue_init(queue_depth, r, 0)
u := &UDPConn{
ptr: r,
@@ -95,11 +95,12 @@ func (u *UDPConn) ReadFromNetaddr(buf []byte) (int, netaddr.IPPort, error) {
if u.fd == 0 {
return 0, netaddr.IPPort{}, errors.New("invalid uring.UDPConn")
}
var idx C.size_t
n := C.receive_into(u.ptr, &idx)
if n < 0 {
nidx := C.receive_into(u.ptr)
if int64(nidx) == -1 {
return 0, netaddr.IPPort{}, errors.New("something wrong")
}
idx := uint32(nidx)
n := uint32(nidx >> 32)
r := &u.reqs[int(idx)]
ip := C.ip(&r.sa)
var ip4 [4]byte