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freebsd-dev/sys/netinet
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Hiren Panchasara 12eeb81fc1 Calculate the correct amount of bytes that are in-flight for a connection as 
suggested by RFC 6675.

Currently differnt places in the stack tries to guess this in suboptimal ways.
The main problem is that current calculations don't take sacked bytes into
account. Sacked bytes are the bytes receiver acked via SACK option. This is
suboptimal because it assumes that network has more outstanding (unacked) bytes
than the actual value and thus sends less data by setting congestion window
lower than what's possible which in turn may cause slower recovery from losses.

As an example, one of the current calculations looks something like this:
snd_nxt - snd_fack + sackhint.sack_bytes_rexmit
New proposal from RFC 6675 is:
snd_max - snd_una - sackhint.sacked_bytes + sackhint.sack_bytes_rexmit
which takes sacked bytes into account which is a new addition to the sackhint
struct. Only thing we are missing from RFC 6675 is isLost() i.e. segment being
considered lost and thus adjusting pipe based on that which makes this
calculation a bit on conservative side.

The approach is very simple. We already process each ack with sack info in
tcp_sack_doack() and extract sack blocks/holes out of it. We'd now also track
this new variable sacked_bytes which keeps track of total sacked bytes reported.

One downside to this approach is that we may get incorrect count of sacked_bytes
if the other end decides to drop sack info in the ack because of memory pressure
or some other reasons. But in this (not very likely) case also the pipe
calculation would be conservative which is okay as opposed to being aggressive
in sending packets into the network.

Next step is to use this more accurate pipe estimation to drive congestion
window adjustments.

In collaboration with:	rrs
Reviewed by:		jason_eggnet dot com, rrs
MFC after:		2 weeks
Sponsored by:		Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D3971
2015-10-28 22:57:51 +00:00
..
cc DCTCP (Data Center TCP) implementation. 2015-01-12 08:33:04 +00:00
khelp
libalias mdoc: fix rendering issues 2015-04-26 11:39:25 +00:00
accf_data.c
accf_dns.c In preparation of merging projects/sendfile, transform bare access to 2014-11-12 09:57:15 +00:00
accf_http.c In preparation of merging projects/sendfile, transform bare access to 2014-11-12 09:57:15 +00:00
cc.h DCTCP (Data Center TCP) implementation. 2015-01-12 08:33:04 +00:00
icmp6.h Implement Enhanced DAD algorithm for IPv6 described in 2015-03-02 17:30:26 +00:00
icmp_var.h
if_atm.c
if_atm.h
if_ether.c Fix regression from r287779, that bite me. If we call m_pullup() 2015-10-07 13:10:26 +00:00
if_ether.h * Do more fine-grained locking: call eventhandlers/free_entry 2015-09-14 16:48:19 +00:00
igmp_var.h - Rename 'struct igmp_ifinfo' into 'struct igmp_ifsoftc', since it really 2015-02-19 22:35:23 +00:00
igmp.c Convert in_ifaddr_lock and in6_ifaddr_lock to rmlock. 2015-07-29 08:12:05 +00:00
igmp.h
in_cksum.c
in_debug.c
in_gif.c Eliminate the use of m_copydata() in gif_encapcheck(). 2015-07-29 14:07:43 +00:00
in_kdtrace.c dd DTrace probe points, translators and a corresponding script 2015-09-13 15:50:55 +00:00
in_kdtrace.h dd DTrace probe points, translators and a corresponding script 2015-09-13 15:50:55 +00:00
in_mcast.c Convert in_ifaddr_lock and in6_ifaddr_lock to rmlock. 2015-07-29 08:12:05 +00:00
in_pcb.c Fix a kernel assertion issue introduced with r286227: 2015-08-08 08:40:36 +00:00
in_pcb.h Use Jenkins hash for TCP syncache. 2015-09-05 10:15:19 +00:00
in_pcbgroup.c Refactor / restructure the RSS code into generic, IPv4 and IPv6 specific 2015-01-18 18:06:40 +00:00
in_proto.c Finish r274118: remove useless fields from struct domain. 2014-11-06 14:39:04 +00:00
in_rmx.c Remove several compat functions from pre-fib era. 2015-10-17 17:26:44 +00:00
in_rss.c Rename rss_soft_m2cpuid() -> rss_soft_m2cpuid_v4() in preparation for 2015-08-29 06:58:30 +00:00
in_rss.h Rename rss_soft_m2cpuid() -> rss_soft_m2cpuid_v4() in preparation for 2015-08-29 06:58:30 +00:00
in_systm.h Where appropriate, use the modern terms for the one true time base 2014-12-21 05:07:11 +00:00
in_var.h Remove several compat functions from pre-fib era. 2015-10-17 17:26:44 +00:00
in.c Fix deletion of ifaddr lle entries when deleting prefix from interface in 2015-10-18 12:26:25 +00:00
in.h Provide functions to determine presence of a given address 2015-04-17 11:57:06 +00:00
ip6.h Eliminate use of M_EXT in IP6_EXTHDR_CHECK() by trimming a redundant 2014-10-05 06:28:53 +00:00
ip_carp.c * Do more fine-grained locking: call eventhandlers/free_entry 2015-09-14 16:48:19 +00:00
ip_carp.h Merge 'struct ip6protosw' and 'struct protosw' into one. Now we have 2014-08-08 01:57:15 +00:00
ip_divert.c Convert netinet6/ to use new routing API. 2014-11-04 15:39:56 +00:00
ip_divert.h
ip_dummynet.h ECN marking implenetation for dummynet. 2014-06-01 07:28:24 +00:00
ip_ecn.c
ip_ecn.h Remove unneded #include "opt_inet.h". 2015-07-31 09:02:28 +00:00
ip_encap.c Fix possible use after free in encap[46]_input(). 2015-06-18 18:28:38 +00:00
ip_encap.h Merge 'struct ip6protosw' and 'struct protosw' into one. Now we have 2014-08-08 01:57:15 +00:00
ip_fastfwd.c Remove incorrect layering violating code that: 2015-01-12 09:41:12 +00:00
ip_fw.h Make rule table kernel-index rewriting support any kind of objects. 2015-04-27 08:29:39 +00:00
ip_gre.c o Use new function ip_fillid() in all places throughout the kernel, 2015-04-01 22:26:39 +00:00
ip_icmp.c Convert in_ifaddr_lock and in6_ifaddr_lock to rmlock. 2015-07-29 08:12:05 +00:00
ip_icmp.h Where appropriate, use the modern terms for the one true time base 2014-12-21 05:07:11 +00:00
ip_id.c Provide a comment explaining issues with the counter(9) trick, so that 2015-04-02 14:22:59 +00:00
ip_input.c Replace rss_m2cpuid with rss_soft_m2cpuid_v4 for ip_direct_nh.nh_m2cpuid, 2015-09-06 20:20:48 +00:00
ip_ipsec.c Turning on IPSEC used to introduce a slight amount of performance 2015-10-27 00:42:15 +00:00
ip_ipsec.h Remove flag/flags argument from the following functions: 2014-12-11 18:35:34 +00:00
ip_mroute.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
ip_mroute.h
ip_options.c Use M_WRITABLE() and M_LEADINGSPACE() rather than checking M_EXT and 2015-01-06 14:32:28 +00:00
ip_options.h Make net.inet.ip.sourceroute, net.inet.ip.accept_sourceroute, and 2014-09-15 07:20:40 +00:00
ip_output.c Simplify ip[6] simploop: 2015-08-08 15:58:35 +00:00
ip_reass.c Fix RSS build - netisr input / NETISR_IP_DIRECT is used here. 2015-04-15 00:57:21 +00:00
ip_var.h fix a typo in a comment 2015-07-18 15:28:32 +00:00
ip.h Since the IETF has redefined the meaning of the tos field to accommodate 2015-07-18 06:48:30 +00:00
pim_var.h Merge 'struct ip6protosw' and 'struct protosw' into one. Now we have 2014-08-08 01:57:15 +00:00
pim.h
raw_ip.c Convert in_ifaddr_lock and in6_ifaddr_lock to rmlock. 2015-07-29 08:12:05 +00:00
sctp_asconf.c Provide consistent error causes whenever an ABORT chunk is sent. 2015-07-27 22:35:54 +00:00
sctp_asconf.h
sctp_auth.c Use __func__ instead of __FUNCTION__. 2015-10-19 11:17:54 +00:00
sctp_auth.h Use a consistent type for the number of HMAC algorithms. 2014-09-16 14:20:33 +00:00
sctp_bsd_addr.c Minimize the usage of SCTP_BUF_IS_EXTENDED. 2015-01-10 20:49:57 +00:00
sctp_bsd_addr.h
sctp_cc_functions.c Fix and cleanup the debug information. This has no user-visible changes. 2015-05-28 16:00:23 +00:00
sctp_constants.h Ensure that ERROR chunks are always padded by implementing this 2015-09-11 13:54:33 +00:00
sctp_crc32.c
sctp_crc32.h
sctp_dtrace_declare.h
sctp_dtrace_define.h
sctp_header.h Cleanup the handling of error causes for ERROR chunks. This fixes 2015-09-12 17:08:51 +00:00
sctp_indata.c Cleanup the handling of error causes for ERROR chunks. This fixes 2015-09-12 17:08:51 +00:00
sctp_indata.h Don't take the port numbers for packets containing ABORT chunks from 2015-08-02 16:07:30 +00:00
sctp_input.c When processing a cookie, any mismatch in port numbers or the vtag results 2015-10-26 21:19:49 +00:00
sctp_input.h Add FIB support for SCTP. 2015-06-17 15:20:14 +00:00
sctp_lock_bsd.h
sctp_os_bsd.h Move including netinet/icmp6.h around to avoid a problem when including 2015-07-25 18:26:09 +00:00
sctp_os.h
sctp_output.c Use __func__ instead of __FUNCTION__. 2015-10-19 11:17:54 +00:00
sctp_output.h Fix an issue with MAC OS locking and also optimize the case 2015-07-24 14:09:03 +00:00
sctp_pcb.c Use __func__ instead of __FUNCTION__. 2015-10-19 11:17:54 +00:00
sctp_pcb.h Add FIB support for SCTP. 2015-06-17 15:20:14 +00:00
sctp_peeloff.c Add a SCTP socket option to limit the cwnd for each path. 2015-03-10 19:49:25 +00:00
sctp_peeloff.h
sctp_ss_functions.c
sctp_structs.h Fix several problems with Stream Reset. 2015-07-22 11:30:37 +00:00
sctp_syscalls.c Fix two KTRACE related bugs. 2015-06-19 21:55:12 +00:00
sctp_sysctl.c Fix the exporting of SCTP association states to userland. Without this, 2015-08-29 09:14:32 +00:00
sctp_sysctl.h Remove redundant 'man page' 2015-09-15 21:16:45 +00:00
sctp_timer.c Fix the timeout for INIT retransmissions in the case where RTO_MIN is 2015-10-13 18:27:55 +00:00
sctp_timer.h
sctp_uio.h Export the ssthresh value per SCTP path via the sysctl interface. 2015-07-07 06:34:28 +00:00
sctp_usrreq.c Use __func__ instead of __FUNCTION__. 2015-10-19 11:17:54 +00:00
sctp_var.h Stop the heartbeat timer when removing a net. 2015-06-14 17:48:44 +00:00
sctp.h Cleanup the handling of error causes for ERROR chunks. This fixes 2015-09-12 17:08:51 +00:00
sctputil.c Use __func__ instead of __FUNCTION__. 2015-10-19 11:17:54 +00:00
sctputil.h Fix the exporting of SCTP association states to userland. Without this, 2015-08-29 09:14:32 +00:00
siftr.c Move the SIFTR DTrace probe out of the writing thread context 2015-04-30 17:43:40 +00:00
tcp_debug.c
tcp_debug.h
tcp_fsm.h
tcp_hostcache.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
tcp_hostcache.h Add scope zone id to the in_endpoints and hc_metrics structures. 2014-09-10 16:26:18 +00:00
tcp_input.c Calculate the correct amount of bytes that are in-flight for a connection as 2015-10-28 22:57:51 +00:00
tcp_lro.c Fix leak in tcp_lro_rx. Simply clearing M_PKTHDR isn't enough, any tags 2015-06-30 17:19:58 +00:00
tcp_lro.h
tcp_offload.c Convert netinet6/ to use new routing API. 2014-11-04 15:39:56 +00:00
tcp_offload.h
tcp_output.c There are times when it would be really nice to have a record of the last few 2015-10-14 00:35:37 +00:00
tcp_pcap.c Hopefully also unbreak VIMAGE kernels replacing the &V_... with 2015-10-15 01:44:32 +00:00
tcp_pcap.h There are times when it would be really nice to have a record of the last few 2015-10-14 00:35:37 +00:00
tcp_reass.c Eliminate nd6_nud_hint() and its TCP bindings. 2015-09-27 05:29:34 +00:00
tcp_sack.c Calculate the correct amount of bytes that are in-flight for a connection as 2015-10-28 22:57:51 +00:00
tcp_seq.h
tcp_subr.c Turning on IPSEC used to introduce a slight amount of performance 2015-10-27 00:42:15 +00:00
tcp_syncache.c Use Jenkins hash for TCP syncache. 2015-09-05 10:15:19 +00:00
tcp_syncache.h Use Jenkins hash for TCP syncache. 2015-09-05 10:15:19 +00:00
tcp_timer.c Fix an unnecessarily aggressive behavior where mtu clamping begins on first 2015-10-14 06:57:28 +00:00
tcp_timer.h Put r284245 back in place: If at first this fix was seen as a temporary 2015-08-30 13:44:39 +00:00
tcp_timewait.c Decompose TCP INP_INFO lock to increase short-lived TCP connections scalability: 2015-08-03 12:13:54 +00:00
tcp_usrreq.c There are times when it would be really nice to have a record of the last few 2015-10-14 00:35:37 +00:00
tcp_var.h Calculate the correct amount of bytes that are in-flight for a connection as 2015-10-28 22:57:51 +00:00
tcp.h There are times when it would be really nice to have a record of the last few 2015-10-14 00:35:37 +00:00
tcpip.h
toecore.c Replace toe_nd6_resolve() with nd6_resolve(). 2015-09-22 19:05:44 +00:00
toecore.h * Convert TOE framework to use new routing api. 2014-10-25 18:25:00 +00:00
udp_usrreq.c get_inpcbinfo() and get_pcblist() are UDP local functions and 2015-08-27 15:27:41 +00:00
udp_var.h get_inpcbinfo() and get_pcblist() are UDP local functions and 2015-08-27 15:27:41 +00:00
udp.h
udplite.h