On Sun, Jan 24, 2016 at 8:32 AM, Ben Pfaff <b...@ovn.org> wrote:
> Before this commit, emc_processing() copied a netdev_flow_key if there was
> no exact-match cache (EMC) hit. This commit eliminates the copy by
> constructing the netdev_flow_key in the place it would be copied.
>
> Found by inspection.
>
> Shahbaz (CCed) reports that this reduces the cost of an EMC miss by 72
> cycles in his test case in which the EMC is disabled. Presumably this
> is similarly valuable in cases where the EMC merely has few hits.
>
> CC: Muhammad Shahbaz <mshah...@cs.princeton.edu>
> Signed-off-by: Ben Pfaff <b...@ovn.org>
>
Logic looks good to me.
Acked-by: Andy Zhou <az...@ovn.org>
I think Daniele is testing on performance impact on this patch. so it is
may be worthwhile
to wait for his input before pushing the change.
---
> AUTHORS | 1 +
> lib/dpif-netdev.c | 17 ++++++++---------
> 2 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/AUTHORS b/AUTHORS
> index 7ae64d3..420aa2d 100644
> --- a/AUTHORS
> +++ b/AUTHORS
> @@ -352,6 +352,7 @@ Mike Kruze mkr...@nicira.com
> Min Chen ustcer.tonyc...@gmail.com
> Mikael Doverhag mdover...@nicira.com
> Mrinmoy Das mr...@ixiacom.com
> +Muhammad Shahbaz mshah...@cs.princeton.edu
> Murali R muralir...@gmail.com
> Nagi Reddy Jonnala njonn...@brocade.com
> Niels van Adrichem n.l.m.vanadric...@tudelft.nl
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index cd72e62..97c4cde 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
> + * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2016 Nicira, Inc.
> *
> * Licensed under the Apache License, Version 2.0 (the "License");
> * you may not use this file except in compliance with the License.
> @@ -3210,7 +3210,6 @@ emc_processing(struct dp_netdev_pmd_thread *pmd,
> struct dp_packet **packets,
> struct packet_batch batches[], size_t *n_batches)
> {
> struct emc_cache *flow_cache = &pmd->flow_cache;
> - struct netdev_flow_key key;
> size_t i, notfound_cnt = 0;
>
> for (i = 0; i < cnt; i++) {
> @@ -3226,20 +3225,20 @@ emc_processing(struct dp_netdev_pmd_thread *pmd,
> struct dp_packet **packets,
> OVS_PREFETCH(dp_packet_data(packets[i+1]));
> }
>
> - miniflow_extract(packets[i], &key.mf);
> - key.len = 0; /* Not computed yet. */
> - key.hash = dpif_netdev_packet_get_rss_hash(packets[i], &key.mf);
> + struct netdev_flow_key *key = &keys[notfound_cnt];
> + miniflow_extract(packets[i], &key->mf);
> + key->len = 0; /* Not computed yet. */
> + key->hash = dpif_netdev_packet_get_rss_hash(packets[i], &key->mf);
>
> - flow = emc_lookup(flow_cache, &key);
> + flow = emc_lookup(flow_cache, key);
> if (OVS_LIKELY(flow)) {
> - dp_netdev_queue_batches(packets[i], flow, &key.mf, batches,
> + dp_netdev_queue_batches(packets[i], flow, &key->mf, batches,
> n_batches);
> } else {
> if (i != notfound_cnt) {
> dp_packet_swap(&packets[i], &packets[notfound_cnt]);
> }
> -
> - keys[notfound_cnt++] = key;
> + notfound_cnt++;
> }
> }
>
> --
> 2.1.3
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
>
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
