[dpdk-dev] 回复: [RFC 3/5] eal: lcore state FINISHED is not required
From: Feifei Wang <hidden>
Date: 2021-02-25 08:44:33
Hi, Honnappa
-----Original Message----- From: Honnappa Nagarahalli <redacted> Sent: Thursday, February 25, 2021 5:20 AM To: hemant.agrawal@nxp.com; Nipun.gupta@nxp.com; jerinj@marvell.com; Harry van Haaren [off-list ref]; Bruce Richardson [off-list ref]; Dmitry Kozlyuk [off-list ref]; Narcisa Ana Maria Vasile [off-list ref]; Dmitry Malloy [off-list ref]; Pallavi Kadam [off-list ref] Cc: dev@dpdk.org; Honnappa Nagarahalli [off-list ref]; Ruifeng Wang [off-list ref]; Feifei Wang (Arm Technology China) [off-list ref]; nd [off-list ref] Subject: [RFC 3/5] eal: lcore state FINISHED is not required FINISHED state seems to be used to indicate that the worker's update of the 'state' is not visible to other threads. There seems to be no requirement to have such a state.
I am not sure "FINISHED" is necessary to be removed, and I propose some of my profiles for discussion.
There are three states for lcore now:
"WAIT": indicate lcore can start working
"RUNNING": indicate lcore is working
"FINISHED": indicate lcore has finished its working and wait to be reset
From the description above, we can find "FINISHED" is different from "WAIT", it can shows that lcore
has done the work and finished it. Thus, if we remove "FINISHED", maybe we will not know whether
the lcore finishes its work or just doesn't start, because this two state has the same tag "WAIT".
Furthermore, consider such a scenario:
Core 1 need to monitor Core 2 state, if Core 2 finishes one task, Core 1 can start its working.
However, if there is only one tag "WAIT", Core 1 maybe start its work at the wrong time, when
Core 2 still does not start its task at state "WAIT".
This is just my guess, and at present, there is no similar application scenario in dpdk.
On the other hand, if we decide to remove "FINISHED", please consider the following files:
1. lib/librte_eal/linux/eal_thread.c: line 31
lib/librte_eal/windows/eal_thread.c: line 22
lib/librte_eal/freebsd/eal_thread.c: line 31
2. lib/librte_eal/include/rte_launch.h: line 24, 44, 121, 123, 131
3. examples/l2fwd-keepalive/main.c: line 510
rte_eal_wait_lcore(id_core) can be removed. Because the core state has been checked as "WAIT",
this is a redundant operation
Best Regards
Feifei
quoted hunk
Signed-off-by: Honnappa Nagarahalli <redacted> Reviewed-by: Ola Liljedahl <redacted> --- drivers/event/dpaa2/dpaa2_eventdev_selftest.c | 2 +- drivers/event/octeontx/ssovf_evdev_selftest.c | 2 +- drivers/event/sw/sw_evdev_selftest.c | 4 ++-- examples/l2fwd-keepalive/main.c | 2 +- lib/librte_eal/common/eal_common_launch.c | 7 ++----- lib/librte_eal/freebsd/eal_thread.c | 2 +- lib/librte_eal/linux/eal_thread.c | 8 +------- lib/librte_eal/windows/eal_thread.c | 8 +------- 8 files changed, 10 insertions(+), 25 deletions(-)diff --git a/drivers/event/dpaa2/dpaa2_eventdev_selftest.cb/drivers/event/dpaa2/dpaa2_eventdev_selftest.c index cd7311a94..bbbd20951 100644--- a/drivers/event/dpaa2/dpaa2_eventdev_selftest.c +++ b/drivers/event/dpaa2/dpaa2_eventdev_selftest.c@@ -468,7 +468,7 @@ wait_workers_to_join(int lcore, const rte_atomic32_t*count) RTE_SET_USED(count); print_cycles = cycles = rte_get_timer_cycles(); -while (rte_eal_get_lcore_state(lcore) != FINISHED) { +while (rte_eal_get_lcore_state(lcore) != WAIT) { uint64_t new_cycles = rte_get_timer_cycles(); if (new_cycles - print_cycles > rte_get_timer_hz()) { diff --git a/drivers/event/octeontx/ssovf_evdev_selftest.c b/drivers/event/octeontx/ssovf_evdev_selftest.c index 528f99dd8..d7b0d2211 100644--- a/drivers/event/octeontx/ssovf_evdev_selftest.c +++ b/drivers/event/octeontx/ssovf_evdev_selftest.c@@ -579,7 +579,7 @@ wait_workers_to_join(int lcore, const rte_atomic32_t*count) RTE_SET_USED(count); print_cycles = cycles = rte_get_timer_cycles(); -while (rte_eal_get_lcore_state(lcore) != FINISHED) { +while (rte_eal_get_lcore_state(lcore) != WAIT) { uint64_t new_cycles = rte_get_timer_cycles(); if (new_cycles - print_cycles > rte_get_timer_hz()) { diff --git a/drivers/event/sw/sw_evdev_selftest.c b/drivers/event/sw/sw_evdev_selftest.c index e4bfb3a0f..7847a8645 100644--- a/drivers/event/sw/sw_evdev_selftest.c +++ b/drivers/event/sw/sw_evdev_selftest.c@@ -3138,8 +3138,8 @@ worker_loopback(struct test *t, uint8_tdisable_implicit_release) rte_eal_remote_launch(worker_loopback_worker_fn, t, w_lcore); print_cycles = cycles = rte_get_timer_cycles(); -while (rte_eal_get_lcore_state(p_lcore) != FINISHED || -rte_eal_get_lcore_state(w_lcore) != FINISHED) { +while (rte_eal_get_lcore_state(p_lcore) != WAIT || +rte_eal_get_lcore_state(w_lcore) != WAIT) { rte_service_run_iter_on_app_lcore(t->service_id, 1);diff --git a/examples/l2fwd-keepalive/main.c b/examples/l2fwd-keepalive/main.c index e4c2b2793..dd777c46a 100644--- a/examples/l2fwd-keepalive/main.c +++ b/examples/l2fwd-keepalive/main.c@@ -506,7 +506,7 @@ dead_core(__rte_unused void *ptr_data, const intid_core) if (terminate_signal_received) return; printf("Dead core %i - restarting..\n", id_core); -if (rte_eal_get_lcore_state(id_core) == FINISHED) { +if (rte_eal_get_lcore_state(id_core) == WAIT) { rte_eal_wait_lcore(id_core); rte_eal_remote_launch(l2fwd_launch_one_lcore, NULL, id_core); } else { diff --git a/lib/librte_eal/common/eal_common_launch.c b/lib/librte_eal/common/eal_common_launch.c index 34f854ad8..78fd94026 100644--- a/lib/librte_eal/common/eal_common_launch.c +++ b/lib/librte_eal/common/eal_common_launch.c@@ -26,14 +26,11 @@ rte_eal_wait_lcore(unsigned worker_id) if(lcore_config[worker_id].state == WAIT) return 0; -while (lcore_config[worker_id].state != WAIT && - lcore_config[worker_id].state != FINISHED) +while (lcore_config[worker_id].state != WAIT) rte_pause(); rte_rmb(); -/* we are in finished state, go to wait state */ - lcore_config[worker_id].state = WAIT; return lcore_config[worker_id].ret; }@@ -62,7 +59,7 @@ rte_eal_mp_remote_launch(int (*f)(void *), void *arg, if (call_main == CALL_MAIN) { lcore_config[main_lcore].ret = f(arg); -lcore_config[main_lcore].state = FINISHED; +lcore_config[main_lcore].state = WAIT; } return 0;diff --git a/lib/librte_eal/freebsd/eal_thread.cb/lib/librte_eal/freebsd/eal_thread.c index 17b8f3996..6d6f1e2fd 100644--- a/lib/librte_eal/freebsd/eal_thread.c +++ b/lib/librte_eal/freebsd/eal_thread.c@@ -140,7 +140,7 @@ eal_thread_loop(__rte_unused void *arg)lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL; rte_wmb(); -lcore_config[lcore_id].state = FINISHED; +lcore_config[lcore_id].state = WAIT; } /* never reached */diff --git a/lib/librte_eal/linux/eal_thread.cb/lib/librte_eal/linux/eal_thread.c index a0a009104..7b9463df3 100644--- a/lib/librte_eal/linux/eal_thread.c +++ b/lib/librte_eal/linux/eal_thread.c@@ -141,13 +141,7 @@ eal_thread_loop(__rte_unused void *arg)lcore_config[lcore_id].arg = NULL; rte_wmb(); -/* when a service core returns, it should go directly to WAIT - * state, because the application will not lcore_wait() for it. - */ -if (lcore_config[lcore_id].core_role == ROLE_SERVICE) - lcore_config[lcore_id].state = WAIT; -else -lcore_config[lcore_id].state = FINISHED; +lcore_config[lcore_id].state = WAIT; } /* never reached */diff --git a/lib/librte_eal/windows/eal_thread.cb/lib/librte_eal/windows/eal_thread.c index 7a9277c51..35d059a30 100644--- a/lib/librte_eal/windows/eal_thread.c +++ b/lib/librte_eal/windows/eal_thread.c@@ -125,13 +125,7 @@ eal_thread_loop(void *arg __rte_unused)lcore_config[lcore_id].arg = NULL; rte_wmb(); -/* when a service core returns, it should go directly to WAIT - * state, because the application will not lcore_wait() for it. - */ -if (lcore_config[lcore_id].core_role == ROLE_SERVICE) - lcore_config[lcore_id].state = WAIT; -else -lcore_config[lcore_id].state = FINISHED; +lcore_config[lcore_id].state = WAIT; } } -- 2.17.1