diff mbox series

[net-next,1/6] tcp: switch to GSO being always on

Message ID 20180219195652.242663-2-edumazet@google.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series tcp: remove non GSO code | expand

Commit Message

Eric Dumazet Feb. 19, 2018, 7:56 p.m. UTC 
Oleksandr Natalenko reported performance issues with BBR without FQ
packet scheduler that were root caused to lack of SG and GSO/TSO on
his configuration.

In this mode, TCP internal pacing has to setup a high resolution timer
for each MSS sent.

We could implement in TCP a strategy similar to the one adopted
in commit fefa569a9d4b ("net_sched: sch_fq: account for schedule/timers drifts")
or decide to finally switch TCP stack to a GSO only mode.

This has many benefits :

1) Most TCP developments are done with TSO in mind.
2) Less high-resolution timers needs to be armed for TCP-pacing
3) GSO can benefit of xmit_more hint
4) Receiver GRO is more effective (as if TSO was used for real on sender)
   -> Lower ACK traffic
5) Write queues have less overhead (one skb holds about 64KB of payload)
6) SACK coalescing just works.
7) rtx rb-tree contains less packets, SACK is cheaper.

This patch implements the minimum patch, but we can remove some legacy
code as follow ups.

Tested:

On 40Gbit link, one netperf -t TCP_STREAM

BBR+fq:
sg on:  26 Gbits/sec
sg off: 15.7 Gbits/sec   (was 2.3 Gbit before patch)

BBR+pfifo_fast:
sg on:  24.2 Gbits/sec
sg off: 14.9 Gbits/sec  (was 0.66 Gbit before patch !!! )

BBR+fq_codel:
sg on:  24.4 Gbits/sec
sg off: 15 Gbits/sec  (was 0.66 Gbit before patch !!! )

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
---
 include/net/sock.h | 1 +
 net/core/sock.c    | 2 +-
 net/ipv4/tcp.c     | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

Comments

kernel test robot Feb. 20, 2018, 1:22 a.m. UTC | #1 
Hi Eric,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Eric-Dumazet/tcp-remove-non-GSO-code/20180220-064839
reproduce: make htmldocs

All warnings (new ones prefixed by >>):

   net/mac80211/sta_info.h:584: warning: Function parameter or member 'status_stats.retry_count' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'status_stats.lost_packets' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'status_stats.last_tdls_pkt_time' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'msdu_retries' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'msdu_failed' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'status_stats.last_ack' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'tx_stats.packets' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'tx_stats.bytes' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'tx_stats.last_rate' not described in 'sta_info'
   net/mac80211/sta_info.h:584: warning: Function parameter or member 'msdu' not described in 'sta_info'
   include/linux/dma-buf.h:307: warning: Function parameter or member 'cb_excl.cb' not described in 'dma_buf'
   include/linux/dma-buf.h:307: warning: Function parameter or member 'cb_excl.poll' not described in 'dma_buf'
   include/linux/dma-buf.h:307: warning: Function parameter or member 'cb_excl.active' not described in 'dma_buf'
   include/linux/dma-buf.h:307: warning: Function parameter or member 'cb_shared.cb' not described in 'dma_buf'
   include/linux/dma-buf.h:307: warning: Function parameter or member 'cb_shared.poll' not described in 'dma_buf'
   include/linux/dma-buf.h:307: warning: Function parameter or member 'cb_shared.active' not described in 'dma_buf'
   include/linux/dma-fence-array.h:54: warning: Function parameter or member 'work' not described in 'dma_fence_array'
   include/linux/gpio/driver.h:142: warning: Function parameter or member 'request_key' not described in 'gpio_irq_chip'
   include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.sign' not described in 'iio_chan_spec'
   include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.realbits' not described in 'iio_chan_spec'
   include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.storagebits' not described in 'iio_chan_spec'
   include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.shift' not described in 'iio_chan_spec'
   include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.repeat' not described in 'iio_chan_spec'
   include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.endianness' not described in 'iio_chan_spec'
   include/linux/iio/hw-consumer.h:1: warning: no structured comments found
   include/linux/device.h:294: warning: Function parameter or member 'coredump' not described in 'device_driver'
   include/linux/input/sparse-keymap.h:46: warning: Function parameter or member 'sw' not described in 'key_entry'
   include/linux/mtd/rawnand.h:709: warning: Function parameter or member 'timings.sdr' not described in 'nand_data_interface'
   include/linux/mtd/rawnand.h:774: warning: Function parameter or member 'buf' not described in 'nand_op_data_instr'
   include/linux/mtd/rawnand.h:774: warning: Function parameter or member 'buf.in' not described in 'nand_op_data_instr'
   include/linux/mtd/rawnand.h:774: warning: Function parameter or member 'buf.out' not described in 'nand_op_data_instr'
   include/linux/mtd/rawnand.h:820: warning: Function parameter or member 'ctx' not described in 'nand_op_instr'
   include/linux/mtd/rawnand.h:820: warning: Function parameter or member 'ctx.cmd' not described in 'nand_op_instr'
   include/linux/mtd/rawnand.h:820: warning: Function parameter or member 'ctx.addr' not described in 'nand_op_instr'
   include/linux/mtd/rawnand.h:820: warning: Function parameter or member 'ctx.data' not described in 'nand_op_instr'
   include/linux/mtd/rawnand.h:820: warning: Function parameter or member 'ctx.waitrdy' not described in 'nand_op_instr'
   include/linux/mtd/rawnand.h:967: warning: Function parameter or member 'ctx' not described in 'nand_op_parser_pattern_elem'
   include/linux/mtd/rawnand.h:967: warning: Function parameter or member 'ctx.addr' not described in 'nand_op_parser_pattern_elem'
   include/linux/mtd/rawnand.h:967: warning: Function parameter or member 'ctx.data' not described in 'nand_op_parser_pattern_elem'
   include/linux/mtd/rawnand.h:1281: warning: Function parameter or member 'manufacturer.desc' not described in 'nand_chip'
   include/linux/mtd/rawnand.h:1281: warning: Function parameter or member 'manufacturer.priv' not described in 'nand_chip'
   include/linux/regulator/driver.h:221: warning: Function parameter or member 'resume_early' not described in 'regulator_ops'
   drivers/regulator/core.c:4299: warning: Excess function parameter 'state' description in 'regulator_suspend_late'
   arch/s390/include/asm/cio.h:245: warning: Function parameter or member 'esw.esw0' not described in 'irb'
   arch/s390/include/asm/cio.h:245: warning: Function parameter or member 'esw.esw1' not described in 'irb'
   arch/s390/include/asm/cio.h:245: warning: Function parameter or member 'esw.esw2' not described in 'irb'
   arch/s390/include/asm/cio.h:245: warning: Function parameter or member 'esw.esw3' not described in 'irb'
   arch/s390/include/asm/cio.h:245: warning: Function parameter or member 'esw.eadm' not described in 'irb'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_pin' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_unpin' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_res_obj' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_get_sg_table' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_import_sg_table' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_vmap' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_vunmap' not described in 'drm_driver'
   include/drm/drm_drv.h:609: warning: Function parameter or member 'gem_prime_mmap' not described in 'drm_driver'
   include/drm/drm_connector.h:370: warning: Function parameter or member 'margins.left' not described in 'drm_tv_connector_state'
   include/drm/drm_connector.h:370: warning: Function parameter or member 'margins.right' not described in 'drm_tv_connector_state'
   include/drm/drm_connector.h:370: warning: Function parameter or member 'margins.top' not described in 'drm_tv_connector_state'
   include/drm/drm_connector.h:370: warning: Function parameter or member 'margins.bottom' not described in 'drm_tv_connector_state'
   include/drm/drm_vblank.h:63: warning: Function parameter or member 'event.base' not described in 'drm_pending_vblank_event'
   include/drm/drm_vblank.h:63: warning: Function parameter or member 'event.vbl' not described in 'drm_pending_vblank_event'
   include/drm/drm_vblank.h:63: warning: Function parameter or member 'event.seq' not described in 'drm_pending_vblank_event'
   drivers/gpu/drm/tve200/tve200_drv.c:1: warning: no structured comments found
   include/linux/skbuff.h:849: warning: Function parameter or member 'dev_scratch' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'skb_mstamp' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member '__cloned_offset' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'head_frag' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member '__unused' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member '__pkt_type_offset' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'pfmemalloc' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'encapsulation' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'encap_hdr_csum' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'csum_valid' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'csum_complete_sw' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'csum_level' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'inner_protocol_type' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'remcsum_offload' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'offload_fwd_mark' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'offload_mr_fwd_mark' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'sender_cpu' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'reserved_tailroom' not described in 'sk_buff'
   include/linux/skbuff.h:849: warning: Function parameter or member 'inner_ipproto' not described in 'sk_buff'
   include/net/sock.h:234: warning: Function parameter or member 'skc_addrpair' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_portpair' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_ipv6only' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_net_refcnt' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_v6_daddr' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_v6_rcv_saddr' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_cookie' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_listener' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_tw_dr' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_rcv_wnd' not described in 'sock_common'
   include/net/sock.h:234: warning: Function parameter or member 'skc_tw_rcv_nxt' not described in 'sock_common'
   include/net/sock.h:488: warning: Function parameter or member 'sk_backlog.rmem_alloc' not described in 'sock'
   include/net/sock.h:488: warning: Function parameter or member 'sk_backlog.len' not described in 'sock'
   include/net/sock.h:488: warning: Function parameter or member 'sk_backlog.head' not described in 'sock'
   include/net/sock.h:488: warning: Function parameter or member 'sk_backlog.tail' not described in 'sock'
   include/net/sock.h:488: warning: Function parameter or member 'sk_wq_raw' not described in 'sock'
   include/net/sock.h:488: warning: Function parameter or member 'tcp_rtx_queue' not described in 'sock'
>> include/net/sock.h:488: warning: Function parameter or member 'sk_route_forced_caps' not described in 'sock'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'adj_list.upper' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'adj_list.lower' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'gso_partial_features' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'switchdev_ops' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'l3mdev_ops' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'xfrmdev_ops' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'name_assign_type' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'ieee802154_ptr' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'mpls_ptr' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'xdp_prog' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'gro_flush_timeout' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'nf_hooks_ingress' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member '____cacheline_aligned_in_smp' not described in 'net_device'
   include/linux/netdevice.h:1946: warning: Function parameter or member 'qdisc_hash' not described in 'net_device'
   include/linux/phylink.h:56: warning: Function parameter or member '__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising' not described in 'phylink_link_state'
   include/linux/phylink.h:56: warning: Function parameter or member '__ETHTOOL_DECLARE_LINK_MODE_MASK(lp_advertising' not described in 'phylink_link_state'
   include/linux/rcupdate.h:570: ERROR: Unexpected indentation.
   include/linux/rcupdate.h:574: ERROR: Unexpected indentation.
   include/linux/rcupdate.h:578: WARNING: Block quote ends without a blank line; unexpected unindent.
   include/linux/rcupdate.h:580: WARNING: Block quote ends without a blank line; unexpected unindent.
   include/linux/rcupdate.h:580: WARNING: Inline literal start-string without end-string.
   kernel/time/timer.c:1259: ERROR: Unexpected indentation.
   kernel/time/timer.c:1261: ERROR: Unexpected indentation.
   kernel/time/timer.c:1262: WARNING: Block quote ends without a blank line; unexpected unindent.
   include/linux/wait.h:110: WARNING: Block quote ends without a blank line; unexpected unindent.
   include/linux/wait.h:113: ERROR: Unexpected indentation.
   include/linux/wait.h:115: WARNING: Block quote ends without a blank line; unexpected unindent.
   kernel/time/hrtimer.c:1113: WARNING: Block quote ends without a blank line; unexpected unindent.
   kernel/signal.c:327: WARNING: Inline literal start-string without end-string.
   drivers/video/fbdev/core/modedb.c:647: WARNING: Inline strong start-string without end-string.
   drivers/video/fbdev/core/modedb.c:647: WARNING: Inline strong start-string without end-string.
   drivers/video/fbdev/core/modedb.c:647: WARNING: Inline strong start-string without end-string.
   drivers/video/fbdev/core/modedb.c:647: WARNING: Inline strong start-string without end-string.
   include/linux/iio/iio.h:191: ERROR: Unexpected indentation.
   include/linux/iio/iio.h:192: WARNING: Block quote ends without a blank line; unexpected unindent.
   include/linux/iio/iio.h:198: WARNING: Definition list ends without a blank line; unexpected unindent.
   drivers/ata/libata-core.c:5920: ERROR: Unknown target name: "hw".
   drivers/message/fusion/mptbase.c:5052: WARNING: Definition list ends without a blank line; unexpected unindent.
   drivers/tty/serial/serial_core.c:1901: WARNING: Definition list ends without a blank line; unexpected unindent.
   include/linux/mtd/rawnand.h:805: ERROR: Unexpected indentation.
   include/linux/mtd/rawnand.h:1391: WARNING: Inline strong start-string without end-string.
   include/linux/mtd/rawnand.h:1393: WARNING: Inline strong start-string without end-string.
   include/linux/regulator/driver.h:273: ERROR: Unknown target name: "regulator_regmap_x_voltage".
   Documentation/driver-api/slimbus.rst:93: WARNING: Title underline too short.

vim +488 include/net/sock.h

^1da177e Linus Torvalds 2005-04-16 @488  

:::::: The code at line 488 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

:::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
:::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
diff mbox series

Patch

diff --git a/include/net/sock.h b/include/net/sock.h
index 3aa7b7d6e6c7faddf08a77f5c0844049b31d8442..f0f576ff5603eb0f282f37fbf76138a9bdd0f724 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -417,6 +417,7 @@  struct sock {
 	struct page_frag	sk_frag;
 	netdev_features_t	sk_route_caps;
 	netdev_features_t	sk_route_nocaps;
+	netdev_features_t	sk_route_forced_caps;
 	int			sk_gso_type;
 	unsigned int		sk_gso_max_size;
 	gfp_t			sk_allocation;
diff --git a/net/core/sock.c b/net/core/sock.c
index a1fa4a548f1be714c5b505b4f269ffbee5572321..507d8c6c431965242efa19f206a1eef28d0f2cff 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1777,7 +1777,7 @@  void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
 	u32 max_segs = 1;
 
 	sk_dst_set(sk, dst);
-	sk->sk_route_caps = dst->dev->features;
+	sk->sk_route_caps = dst->dev->features | sk->sk_route_forced_caps;
 	if (sk->sk_route_caps & NETIF_F_GSO)
 		sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE;
 	sk->sk_route_caps &= ~sk->sk_route_nocaps;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 48636aee23c31244494b7c7acbc911a7f1823691..4b46a2ae46e3ae89e26e7c0885347ab289f16814 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -453,6 +453,7 @@  void tcp_init_sock(struct sock *sk)
 	sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
 
 	sk_sockets_allocated_inc(sk);
+	sk->sk_route_forced_caps = NETIF_F_GSO;
 }
 EXPORT_SYMBOL(tcp_init_sock);