[S] Change in libosmocore[master]: HACK: Allow io_uring_submit batching just ahead of poll

laforge has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/36364?usp=email ) Change subject: HACK: Allow io_uring_submit batching just ahead of poll ...................................................................... HACK: Allow io_uring_submit batching just ahead of poll Let's add a mode (enabled via the LIBOSMO_IO_URING_BATCH environment variable), where we don't call io_uring_submit() after every operation we add to the submission queue. Rather, do that once before we go into poll. This should massively reduce the amount of io_uring_enter() syscalls we're seeing. Change-Id: Ia27ada909df246f21d110d8ae0b40229aacd579d --- M src/core/osmo_io_uring.c M src/core/select.c 2 files changed, 35 insertions(+), 2 deletions(-) git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/64/36364/1 diff --git a/src/core/osmo_io_uring.c b/src/core/osmo_io_uring.c index 569f150..6801eb4 100644 --- a/src/core/osmo_io_uring.c +++ b/src/core/osmo_io_uring.c @@ -60,6 +60,7 @@ }; static __thread struct osmo_io_uring g_ring; +static bool g_batch = false; static void iofd_uring_cqe(struct io_uring *ring); @@ -90,6 +91,9 @@ { int rc, evfd; + if (getenv("LIBOSMO_IO_URING_BATCH")) + g_batch = true; + rc = io_uring_queue_init(IOFD_URING_ENTRIES, &g_ring.ring, 0); if (rc < 0) osmo_panic("failure during io_uring_queue_init(): %s\n", strerror(-rc)); @@ -175,7 +179,8 @@ } io_uring_sqe_set_data(sqe, msghdr); - io_uring_submit(&g_ring.ring); + if (!g_batch) + io_uring_submit(&g_ring.ring); /* NOTE: This only works if we have one read per fd */ iofd->u.uring.read_msghdr = msghdr; } @@ -315,7 +320,8 @@ OSMO_ASSERT(0); } - io_uring_submit(&g_ring.ring); + if (!g_batch) + io_uring_submit(&g_ring.ring); iofd->u.uring.write_msghdr = msghdr; return 0; @@ -529,4 +535,10 @@ .notify_connected = iofd_uring_notify_connected, }; +void osmo_io_uring_submit(void) +{ + if (g_batch) + io_uring_submit(&g_ring.ring); +} + #endif /* defined(__linux__) */ diff --git a/src/core/select.c b/src/core/select.c index 70047f0..0a4302f 100644 --- a/src/core/select.c +++ b/src/core/select.c @@ -426,12 +426,16 @@ return work; } +void osmo_io_uring_submit(void); + static int _osmo_select_main(int polling) { unsigned int n_poll; int rc; int timeout = 0; + osmo_io_uring_submit(); + /* prepare read and write fdsets */ n_poll = poll_fill_fds(); -- To view, visit https://gerrit.osmocom.org/c/libosmocore/+/36364?usp=email To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: libosmocore Gerrit-Branch: master Gerrit-Change-Id: Ia27ada909df246f21d110d8ae0b40229aacd579d Gerrit-Change-Number: 36364 Gerrit-PatchSet: 1 Gerrit-Owner: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-MessageType: newchange