There are many reasons for reloading of pmd threads:
* reconfiguration of one of the ports.
* Adjusting of static_tx_qid.
* Adding new tx/rx ports.
In many cases EMC is still useful after reload and uninit
will only lead to unnecessary upcalls/classifier lookups.
Such behaviour slows down the datapath. Uninit itself slows
down the reload path. All this factors leads to additional
unexpected latencies/drops on events not directly connected
to current PMD thread.
Lets not uninitialize emc cache on reload path.
'emc_cache_slow_sweep()' and replacements should free all
the old/unwanted entries.
Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
---
In discussion of original patch[1] Pravin Shelar said:
'''
emc cache flows should be free on reload, otherwise flows
might stick around for longer time.
'''
After that (for another reason) slow sweep was introduced.
There are few reasons to move uninit out of reload path
described in commit-message.
So, this patch sent as RFC, because I wanted to hear some
opinions about current situation and drawbacks of such
solution.
Any thoughts?
Thanks.
[1] https://mail.openvswitch.org/pipermail/ovs-dev/2014-August/287852.html
lib/dpif-netdev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index e2b4f39..3bd568d 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -3648,9 +3648,9 @@ pmd_thread_main(void *f_)
ovs_numa_thread_setaffinity_core(pmd->core_id);
dpdk_set_lcore_id(pmd->core_id);
poll_cnt = pmd_load_queues_and_ports(pmd, &poll_list);
+ emc_cache_init(&pmd->flow_cache);
reload:
pmd_alloc_static_tx_qid(pmd);
- emc_cache_init(&pmd->flow_cache);
/* List port/core affinity */
for (i = 0; i < poll_cnt; i++) {
@@ -3697,13 +3697,13 @@ reload:
* reloading the updated configuration. */
dp_netdev_pmd_reload_done(pmd);
- emc_cache_uninit(&pmd->flow_cache);
pmd_free_static_tx_qid(pmd);
if (!exiting) {
goto reload;
}
+ emc_cache_uninit(&pmd->flow_cache);
free(poll_list);
pmd_free_cached_ports(pmd);
return NULL;
--
2.7.4
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