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| author | Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> | 2016-08-18 14:58:35 -0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-08-19 17:09:42 -0700 |
| commit | 4c2f2454964477c66ef57745daab203b71783f66 (patch) | |
| tree | 51f1daf90f01ee0775b82eab4727edbe36a80457 /net/l2tp | |
| parent | 187335cdfec32475677b8ea2e7a165843fc38675 (diff) | |
sctp: linearize early if it's not GSO
Because otherwise when crc computation is still needed it's way more
expensive than on a linear buffer to the point that it affects
performance.
It's so expensive that netperf test gives a perf output as below:
Overhead Command Shared Object Symbol
18,62% netserver [kernel.vmlinux] [k] crc32_generic_shift
2,57% netserver [kernel.vmlinux] [k] __pskb_pull_tail
1,94% netserver [kernel.vmlinux] [k] fib_table_lookup
1,90% netserver [kernel.vmlinux] [k] copy_user_enhanced_fast_string
1,66% swapper [kernel.vmlinux] [k] intel_idle
1,63% netserver [kernel.vmlinux] [k] _raw_spin_lock
1,59% netserver [sctp] [k] sctp_packet_transmit
1,55% netserver [kernel.vmlinux] [k] memcpy_erms
1,42% netserver [sctp] [k] sctp_rcv
# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () port 0 AF_INET
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
212992 212992 12000 10.00 3016.42 2.88 3.78 1.874 2.462
After patch:
Overhead Command Shared Object Symbol
2,75% netserver [kernel.vmlinux] [k] memcpy_erms
2,63% netserver [kernel.vmlinux] [k] copy_user_enhanced_fast_string
2,39% netserver [kernel.vmlinux] [k] fib_table_lookup
2,04% netserver [kernel.vmlinux] [k] __pskb_pull_tail
1,91% netserver [kernel.vmlinux] [k] _raw_spin_lock
1,91% netserver [sctp] [k] sctp_packet_transmit
1,72% netserver [mlx4_en] [k] mlx4_en_process_rx_cq
1,68% netserver [sctp] [k] sctp_rcv
# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () port 0 AF_INET
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
212992 212992 12000 10.00 3681.77 3.83 3.46 2.045 1.849
Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp')
0 files changed, 0 insertions, 0 deletions