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  1. 01 Oct, 2023 3 commits
    • Eric Dumazet's avatar
      tcp: derive delack_max from rto_min · bbf80d71
      Eric Dumazet authored 
      While BPF allows to set icsk->->icsk_delack_max
and/or icsk->icsk_rto_min, we have an ip route
attribute (RTAX_RTO_MIN) to be able to tune rto_min,
but nothing to consequently adjust max delayed ack,
which vary from 40ms to 200 ms (TCP_DELACK_{MIN|MAX}).

This makes RTAX_RTO_MIN of almost no practical use,
unless customers are in big trouble.

Modern days datacenter communications want to set
rto_min to ~5 ms, and the max delayed ack one jiffie
smaller to avoid spurious retransmits.

After this patch, an "rto_min 5" route attribute will
effectively lower max delayed ack timers to 4 ms.

Note in the following ss output, "rto:6 ... ato:4"

$ ss -temoi dst XXXXXX
State Recv-Q Send-Q           Local Address:Port       Peer Address:Port  Process
ESTAB 0      0        [2002:a05:6608:295::]:52950   [2002:a05:6608:297::]:41597
     ino:255134 sk:1001 <->
         skmem:(r0,rb1707063,t872,tb262144,f0,w0,o0,bl0,d0) ts sack
 cubic wscale:8,8 rto:6 rtt:0.02/0.002 ato:4 mss:4096 pmtu:4500
 rcvmss:536 advmss:4096 cwnd:10 bytes_sent:54823160 bytes_acked:54823121
 bytes_received:54823120 segs_out:1370582 segs_in:1370580
 data_segs_out:1370579 data_segs_in:1370578 send 16.4Gbps
 pacing_rate 32.6Gbps delivery_rate 1.72Gbps delivered:1370579
 busy:26920ms unacked:1 rcv_rtt:34.615 rcv_space:65920
 rcv_ssthresh:65535 minrtt:0.015 snd_wnd:65536

While we could argue this patch fixes a bug with RTAX_RTO_MIN,
I do not add a Fixes: tag, so that we can soak it a bit before
asking backports to stable branches.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bbf80d71
    • Eric Dumazet's avatar
      tcp: constify tcp_rto_min() and tcp_rto_min_us() argument · f68a181f
      Eric Dumazet authored 
      Make clear these functions do not change any field from TCP socket.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f68a181f
    • Eric Dumazet's avatar
      net: constify sk_dst_get() and __sk_dst_get() argument · 5033f58d
      Eric Dumazet authored 
      Both helpers only read fields from their socket argument.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5033f58d
  3. 30 Sep, 2023 1 commit
  5. 28 Sep, 2023 11 commits
  7. 22 Sep, 2023 5 commits
    • David S. Miller's avatar
      Merge branch 'mlxsw-multicast' · 5a1b322c
      David S. Miller authored 
      Petr Machata says:

====================
mlxsw: Improve blocks selection for IPv6 multicast forwarding

Amit Cohen writes:

The driver configures two ACL regions during initialization, these regions
are used for IPv4 and IPv6 multicast forwarding. Entries residing in these
two regions match on the {SIP, DIP, VRID} key elements.

Currently for IPv6 region, 9 key blocks are used. This can be improved by
reducing the amount key blocks needed for the IPv6 region to 8. It is
possible to use key blocks that mix subsets of the VRID element with
subsets of the DIP element.

To make this happen, we have to take in account the algorithm that chooses
which key blocks will be used. It is lazy and not the optimal one as it is
a complex task. It searches the block that contains the most elements that
are required, chooses it, removes the elements that appear in the chosen
block and starts again searching the block that contains the most elements.

To optimize the nubmber of the blocks for IPv6 multicast forwarding, handle
the following:

1. Add support for key blocks that mix subsets of the VRID element with
subsets of the DIP element.

2. Prevent the algorithm from chosing another blocks for VRID.
Currently, we have the block 'ipv4_4' which contains 2 sub-elements of
VRID. With the existing algorithm, this block might be chosen, then 8
blocks must be chosen for SIP and DIP and we will get 9 blocks to match on
{SIP, DIP, VRID}. Therefore, replace this block with a new block 'ipv4_5'
that contains 1 element for VRID, this will not be chosen for IPv6 as VRID
element will be broken to several sub-elements. In this way we can get 8
blocks for IPv6 multicast forwarding.

This improvement was tested and indeed 8 blocks are used instead of 9.

v2:
- Resending without changes.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5a1b322c
    • Amit Cohen's avatar
      mlxsw: Edit IPv6 key blocks to use one less block for multicast forwarding · 92953e7a
      Amit Cohen authored 
      Two ACL regions that are configured by the driver during initialization are
the ones used for IPv4 and IPv6 multicast forwarding. Entries residing
in these two regions match on the {SIP, DIP, VRID} key elements.

Currently for IPv6 region, 9 key blocks are used:
* 4 for SIP - 'ipv4_1', 'ipv6_{3,4,5}'
* 4 for DIP - 'ipv4_0', 'ipv6_{0,1,2/2b}'
* 1 for VRID - 'ipv4_4b'

This can be improved by reducing the amount key blocks needed for
the IPv6 region to 8. It is possible to use key blocks that mix subsets of
the VRID element with subsets of the DIP element.
The following key blocks can be used:
* 4 for SIP - 'ipv4_1', 'ipv6_{3,4,5}'
* 1 for subset of DIP - 'ipv4_0'
* 3 for the rest of DIP and subsets of VRID - 'ipv6_{0,1,2/2b}'

To make this happen, add VRID sub-elements as part of existing keys -
'ipv6_{0,1,2/2b}'. Note that one of the sub-elements is called
VRID_ROUTER_MSB and does not contain bit numbers like the rest, as for
Spectrum < 4 this element represents bits 8-10 and for Spectrum-4 it
represents bits 8-11.

Breaking VRID into 3 sub-elements makes the driver use one less block in
IPv6 region for multicast forwarding. The sub-elements can be filled in
blocks that are used for destination IP.

The algorithm in the driver that chooses which key blocks will be used is
lazy and not the optimal one. It searches the block that contains the most
elements that are required, chooses it, removes the elements that appear
in the chosen block and starts again searching the block that contains the
most elements.

When key block 'ipv4_4' is defined, the algorithm might choose it, as it
contains 2 sub-elements of VRID, then 8 blocks must be chosen for SIP and
DIP and we get 9 blocks to match on {SIP, DIP, VRID}. That is why we had to
remove key block 'ipv4_4' in a previous patch and use key block that
contains one field for VRID.

This improvement was tested and indeed 8 blocks are used instead of 9.
Signed-off-by: default avatarAmit Cohen <amcohen@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      92953e7a
    • Amit Cohen's avatar
      mlxsw: spectrum_acl_flex_keys: Add 'ipv4_5b' flex key · c6caabdf
      Amit Cohen authored 
      The previous patch replaced the key block 'ipv4_4' with 'ipv4_5'. The
corresponding block for Spectrum-4 is 'ipv4_4b'. To be consistent, replace
key block 'ipv4_4b' with 'ipv4_5b'.
Signed-off-by: default avatarAmit Cohen <amcohen@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c6caabdf
    • Amit Cohen's avatar
      mlxsw: Add 'ipv4_5' flex key · c2f3e10a
      Amit Cohen authored 
      Currently virtual router ID element is broken to two sub-elements -
'VIRT_ROUTER_LSB' and 'VIRT_ROUTER_MSB'. It was broken as this field is
broken in 'ipv4_4' flex key which is used for IPv4 in Spectrum < 4.
For Spectrum-4, we use 'ipv4_4b' flex key which contains one field for
virtual router, this key is not supported in older ASICs.

Add 'ipv4_5' flex key which is supported in all ASICs and contains one
field for virtual router. Then there is no reason to use 'VIRT_ROUTER_LSB'
and 'VIRT_ROUTER_MSB', remove them and add one element 'VIRT_ROUTER' for
this field.

The motivation is to get rid of 'ipv4_4' flex key, as it might be chosen
for IPv6 multicast forwarding region. This will not allow the improvement
in a following patch. See more details in the cover letter and in a
following patch.
Signed-off-by: default avatarAmit Cohen <amcohen@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c2f3e10a
    • Peter Lafreniere's avatar
      hamradio: baycom: remove useless link in Kconfig · 84c19e65
      Peter Lafreniere authored 
      The Kconfig help text for baycom drivers suggests that more information
on the hardware can be found at <https://www.baycom.de>. The website now
includes no information on their ham radio products other than a mention
that they were once produced by the company, saying:
"The amateur radio equipment is now no longer part and business of BayCom GmbH"

As there is no information relavent to the baycom driver on the site,
remove the link.
Signed-off-by: default avatarPeter Lafreniere <peter@n8pjl.ca>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      84c19e65
  9. 21 Sep, 2023 20 commits
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