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| author | glebius <glebius@FreeBSD.org> | 2012-09-28 18:28:27 +0000 |
|---|---|---|
| committer | glebius <glebius@FreeBSD.org> | 2012-09-28 18:28:27 +0000 |
| commit | 4b29d585cfcde7e84697e4af66a48144fb111e27 (patch) | |
| tree | 66a3fa6f2f977c6c8d808397e65fc31995eab050 /sys/dev/mxge | |
| parent | 186eb51daa2f37de906b898ca8e70b4e60e3e0ce (diff) | |
| download | FreeBSD-src-4b29d585cfcde7e84697e4af66a48144fb111e27.zip FreeBSD-src-4b29d585cfcde7e84697e4af66a48144fb111e27.tar.gz | |
The drbr(9) API appeared to be so unclear, that most drivers in
tree used it incorrectly, which lead to inaccurate overrated
if_obytes accounting. The drbr(9) used to update ifnet stats on
drbr_enqueue(), which is not accurate since enqueuing doesn't
imply successful processing by driver. Dequeuing neither mean
that. Most drivers also called drbr_stats_update() which did
accounting again, leading to doubled if_obytes statistics. And
in case of severe transmitting, when a packet could be several
times enqueued and dequeued it could have been accounted several
times.
o Thus, make drbr(9) API thinner. Now drbr(9) merely chooses between
ALTQ queueing or buf_ring(9) queueing.
- It doesn't touch the buf_ring stats any more.
- It doesn't touch ifnet stats anymore.
- drbr_stats_update() no longer exists.
o buf_ring(9) handles its stats itself:
- It handles br_drops itself.
- br_prod_bytes stats are dropped. Rationale: no one ever
reads them but update of a common counter on every packet
negatively affects performance due to excessive cache
invalidation.
- buf_ring_enqueue_bytes() reduced to buf_ring_enqueue(), since
we no longer account bytes.
o Drivers handle their stats theirselves: if_obytes, if_omcasts.
o mlx4(4), igb(4), em(4), vxge(4), oce(4) and ixv(4) no longer
use drbr_stats_update(), and update ifnet stats theirselves.
o bxe(4) was the most correct driver, it didn't call
drbr_stats_update(), thus it was the only driver accurate under
moderate load. Now it also maintains stats itself.
o ixgbe(4) had already taken stats from hardware, so just
- drop software stats updating.
- take multicast packet count from hardware as well.
o mxge(4) just no longer needs NO_SLOW_STATS define.
o cxgb(4), cxgbe(4) need no change, since they obtain stats
from hardware.
Reviewed by: jfv, gnn
Diffstat (limited to 'sys/dev/mxge')
| -rw-r--r-- | sys/dev/mxge/if_mxge.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/sys/dev/mxge/if_mxge.c b/sys/dev/mxge/if_mxge.c index c61d360..1e51d1b 100644 --- a/sys/dev/mxge/if_mxge.c +++ b/sys/dev/mxge/if_mxge.c @@ -47,8 +47,6 @@ __FBSDID("$FreeBSD$"); #include <sys/sx.h> #include <sys/taskqueue.h> -/* count xmits ourselves, rather than via drbr */ -#define NO_SLOW_STATS #include <net/if.h> #include <net/if_arp.h> #include <net/ethernet.h> |
