Commit Graph

139 Commits

Author SHA1 Message Date
Bodong Wang
7f0d11c7e0 net/mlx5: Add host params change event
In Embedded CPU (EC) configurations, the EC driver needs to know when
the number of virtual functions change on the corresponding PF at the
host side. This is required so the EC driver can create or destroy
representor net devices that represent the VFs ports.

Whenever a change in the number of VFs occurs, firmware will generate an
event towards the EC which will trigger a work to complete the rest of
the handling. The specifics of the handling will be introduced in a
downstream patch.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2019-02-14 12:14:42 -08:00
Bodong Wang
591905ba96 net/mlx5: Introduce Mellanox SmartNIC and modify page management logic
Mellanox's SmartNIC combines embedded CPU(e.g, ARM) processing power
with advanced network offloads to accelerate a multitude of security,
networking and storage applications.

With the introduction of the SmartNIC, there is a new PCI function
called Embedded CPU Physical Function(ECPF). And it's possible for a
PF to get its ICM pages from the ECPF PCI function. Driver shall
identify if it is running on such a function by reading a bit in
the initialization segment.

When firmware asks for pages, it would issue a page request event
specifying how many pages it requests and for which function. That
driver responds with a manage_pages command providing the requested
pages along with an indication for which function it is providing these
pages.

The encoding before this patch was as follows:
    function_id == 0: pages are requested for the function receiving
                      the EQE.
    function_id != 0: pages are requested for VF identified by the
                      function_id value

A new one bit field in the EQE identifies that pages are requested for
the ECPF.

The notion of page_supplier can be introduced here and to support that,
manage pages and query pages were modified so firmware can distinguish
the following cases:

1. Function provides pages for itself
2. PF provides pages for its VF
3. ECPF provides pages to itself
4. ECPF provides pages for another function

This distinction is possible through the introduction of the bit
"embedded_cpu_function" in query_pages, manage_pages and page request
EQE.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2019-02-14 12:14:41 -08:00
Bodong Wang
20bbf22a62 net/mlx5: Use void pointer as the type in address_of macro
Better to use void * and avoid unnecessary casts.

This patch doesn't change any functionality.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2019-02-14 12:14:41 -08:00
Moni Shoua
46861e3e88 net/mlx5: Set ODP SRQ support in firmware
To avoid compatibility issue with older kernels the firmware doesn't
allow SRQ to work with ODP unless kernel asks for it.

Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
2019-02-03 12:49:59 +02:00
Tariq Toukan
5e0d2eef77 net/mlx5e: XDP, Support Enhanced Multi-Packet TX WQE
Add support for the HW feature of multi-packet WQE in XDP
xmit flow.

The conventional TX descriptor (WQE, Work Queue Element) serves
a single packet. Our HW has support for multi-packet WQE (MPWQE)
in which a single descriptor serves multiple TX packets.

This reduces both the PCI overhead and the CPU cycles wasted on
writing them.

In this patch we add support for the HW feature, which is supported
starting from ConnectX-5.

Performance:
Tested packet rate for UDP 64Byte multi-stream over ConnectX-5 NICs.
CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz

XDP_TX:
We see a huge gain on single port ConnectX-5, and reach the 100 Mpps
milestone.
* Single-port HCA:
	Before:   70 Mpps
	After:   100 Mpps (+42.8%)

* Dual-port HCA:
	Before: 51.7 Mpps
	After:  57.3 Mpps (+10.8%)

* In both cases we tested traffic on one port and for now On Dual-port HCAs
  we see only small gain, we are working to overcome this bottleneck, but
  for the moment only with experimental firmware on dual port HCAs we can
  reach the wanted numbers as seen on Single-port HCAs.

XDP_REDIRECT:
Redirect from (A) ConnectX-5 to (B) ConnectX-5.
Due to a setup limitation, (A) and (B) are on different NUMA nodes,
so absolute performance numbers are not optimal.
Note:
  Below is the transmit rate of (B), not the redirect rate of (A)
  which is in some cases higher.

* (B) is single-port:
	Before:   77 Mpps
	After:    90 Mpps (+16.8%)

* (B) is dual-port:
	Before:  61 Mpps
	After:   72 Mpps (+18%)

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-12-20 22:54:19 -08:00
Eyal Davidovich
fd4572b3ff net/mlx5: Add monitor commands layout and event data
Will be used in downstream patch to monitor counter changes
by the HCA and report it to the driver by an event.
The driver will update its counters cached data accordingly.

Signed-off-by: Eyal Davidovich <eyald@mellanox.com>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-12-10 14:00:08 -08:00
Tariq Toukan
6254adeb1f net/mlx5: Use helper to get CQE opcode
Introduce and use a helper that extracts the opcode
from a CQE (completion queue entry) structure.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-12-09 18:16:16 -08:00
Saeed Mahameed
0f597ed435 net/mlx5: EQ, Introduce atomic notifier chain subscription API
Use atomic_notifier_chain to fire firmware events at internal mlx5 core
components such as eswitch/fpga/clock/FW tracer/etc.., this is to
avoid explicit calls from low level mlx5_core to upper components and to
simplify the mlx5_core API for future developments.

Simply provide register/unregister notifiers API and call the notifier
chain on firmware async events.

Example: to subscribe to a FW event:
struct mlx5_nb port_event;

MLX5_NB_INIT(&port_event, port_event_handler, PORT_CHANGE);
mlx5_eq_notifier_register(mdev, &port_event);

where:
 - port_event_handler is the notifier block callback.
 - PORT_EVENT is the suffix of MLX5_EVENT_TYPE_PORT_CHANGE.

The above will guarantee that port_event_handler will receive all FW
events of the type MLX5_EVENT_TYPE_PORT_CHANGE.

To receive all FW/HW events one can subscribe to
MLX5_EVENT_TYPE_NOTIFY_ANY.

The next few patches will start moving all mlx5 core components to use
this new API and cleanup mlx5_eq_async_int misx handler from component
explicit calls and specific logic.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-11-26 13:39:33 -08:00
Moni Shoua
c99fefea2c net/mlx5: Enumerate page fault types
Give meaningful names to type of WQE page faults.

Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
2018-11-12 22:20:47 +02:00
Saeed Mahameed
186daf0c20 Merge branch 'mlx5-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux into net-next
mlx5 updates for both net-next and rdma-next

* 'mlx5-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux: (21 commits)
  net/mlx5: Expose DC scatter to CQE capability bit
  net/mlx5: Update mlx5_ifc with DEVX UID bits
  net/mlx5: Set uid as part of DCT commands
  net/mlx5: Set uid as part of SRQ commands
  net/mlx5: Set uid as part of SQ commands
  net/mlx5: Set uid as part of RQ commands
  net/mlx5: Set uid as part of QP commands
  net/mlx5: Set uid as part of CQ commands
  net/mlx5: Rename incorrect naming in IFC file
  net/mlx5: Export packet reformat alloc/dealloc functions
  net/mlx5: Pass a namespace for packet reformat ID allocation
  net/mlx5: Expose new packet reformat capabilities
  {net, RDMA}/mlx5: Rename encap to reformat packet
  net/mlx5: Move header encap type to IFC header file
  net/mlx5: Break encap/decap into two separated flow table creation flags
  net/mlx5: Add support for more namespaces when allocating modify header
  net/mlx5: Export modify header alloc/dealloc functions
  net/mlx5: Add proper NIC TX steering flow tables support
  net/mlx5: Cleanup flow namespace getter switch logic
  net/mlx5: Add memic command opcode to command checker
  ...

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-10-17 14:13:36 -07:00
Feras Daoud
fcd29ad17c net/mlx5: Add Fast teardown support
Today mlx5 devices support two teardown modes:
1- Regular teardown
2- Force teardown

This change introduces the enhanced version of the "Force teardown" that
allows SW to perform teardown in a faster way without the need to reclaim
all the pages.

Fast teardown provides the following advantages:
1- Fix a FW race condition that could cause command timeout
2- Avoid moving to polling mode
3- Close the vport to prevent PCI ACK to be sent without been scatter
to memory

Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-10-03 16:18:00 -07:00
Mark Bloch
8ce7825796 net/mlx5: Add proper NIC TX steering flow tables support
Extend the ability to add steering rules to NIC TX flow tables.
For now, we are only adding TX bypass (egress) which is used by the RDMA
side. This will allow to shape outgoing traffic and tweak it if needed, for
example performing encapsulation or rewriting headers.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
2018-09-05 07:56:33 +03:00
Eran Ben Elisha
cc9c82a866 net/mlx5: Rename modify/query_vport state related enums
Modify and query vport state commands share the same admin_state and
op_mod values, rename the enums to fit them both.

In addition, remove the esw prefix from the admin state enum as this
also applied for vnic.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08 19:34:54 -07:00
Feras Daoud
c71ad41ccb net/mlx5: FW tracer, events handling
The tracer has one event, event 0x26, with two subtypes:
- Subtype 0: Ownership change
- Subtype 1: Traces available

An ownership change occurs in the following cases:
1- Owner releases his ownership, in this case, an event will be
sent to inform others to reattempt acquire ownership.
2- Ownership was taken by a higher priority tool, in this case
the owner should understand that it lost ownership, and go through
tear down flow.

The second subtype indicates that there are traces in the trace buffer,
in this case, the driver polls the tracer buffer for new traces, parse
them and prepares the messages for printing.

The HW starts tracing from the first address in the tracer buffer.
Driver receives an event notifying that new trace block exists.
HW posts a timestamp event at the last 8B of every 256B block.
Comparing the timestamp to the last handled timestamp would indicate
that this is a new trace block. Once the new timestamp is detected,
the entire block is considered valid.

Block validation and parsing, should be done after copying the current
block to a different location, in order to avoid block overwritten
during processing.

Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-07-23 15:01:11 -07:00
Tariq Toukan
e2abdcf1d2 net/mlx5: Better return types for CQE API
Reduce sizes of return types.
Use bool for binary indication.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-07-18 14:33:25 -07:00
Yishai Hadas
38b7ca927d net/mlx5: Expose DEVX specification
This patch updates the mlx5_ifc structures and
command interface to support DEVX.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
2018-06-19 19:31:31 +03:00
Linus Torvalds
a1cdde8c41 Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull rdma updates from Jason Gunthorpe:
 "This has been a quiet cycle for RDMA, the big bulk is the usual
  smallish driver updates and bug fixes. About four new uAPI related
  things. Not as much Szykaller patches this time, the bugs it finds are
  getting harder to fix.

  Summary:

   - More work cleaning up the RDMA CM code

   - Usual driver bug fixes and cleanups for qedr, qib, hfi1, hns,
     i40iw, iw_cxgb4, mlx5, rxe

   - Driver specific resource tracking and reporting via netlink

   - Continued work for name space support from Parav

   - MPLS support for the verbs flow steering uAPI

   - A few tricky IPoIB fixes improving robustness

   - HFI1 driver support for the '16B' management packet format

   - Some auditing to not print kernel pointers via %llx or similar

   - Mark the entire 'UCM' user-space interface as BROKEN with the
     intent to remove it entirely. The user space side of this was long
     ago replaced with RDMA-CM and syzkaller is finding bugs in the
     residual UCM interface nobody wishes to fix because nobody uses it.

   - Purge more bogus BUG_ON's from Leon

   - 'flow counters' verbs uAPI

   - T10 fixups for iser/isert, these are Acked by Martin but going
     through the RDMA tree due to dependencies"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (138 commits)
  RDMA/mlx5: Update SPDX tags to show proper license
  RDMA/restrack: Change SPDX tag to properly reflect license
  IB/hfi1: Fix comment on default hdr entry size
  IB/hfi1: Rename exp_lock to exp_mutex
  IB/hfi1: Add bypass register defines and replace blind constants
  IB/hfi1: Remove unused variable
  IB/hfi1: Ensure VL index is within bounds
  IB/hfi1: Fix user context tail allocation for DMA_RTAIL
  IB/hns: Use zeroing memory allocator instead of allocator/memset
  infiniband: fix a possible use-after-free bug
  iw_cxgb4: add INFINIBAND_ADDR_TRANS dependency
  IB/isert: use T10-PI check mask definitions from core layer
  IB/iser: use T10-PI check mask definitions from core layer
  RDMA/core: introduce check masks for T10-PI offload
  IB/isert: fix T10-pi check mask setting
  IB/mlx5: Add counters read support
  IB/mlx5: Add flow counters read support
  IB/mlx5: Add flow counters binding support
  IB/mlx5: Add counters create and destroy support
  IB/uverbs: Add support for flow counters
  ...
2018-06-07 13:04:07 -07:00
Ilan Tayari
1f0cf89b09 net/mlx5: Add FPGA QP error event
The FPGA queue pair (QP) event fires whenever a QP on the FPGA
transitions to the error state.

At this stage, this event is unrecoverable, it may become recoverable
in the future.

Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Adi Nissim <adin@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-31 15:35:38 -04:00
Ilan Tayari
1865ea9adb net/mlx5: Add temperature warning event to log
Temperature warning event is sent by FW to indicate high temperature
as detected by one of the sensors on the board.
Add handling of this event by writing the numbers of the alert sensors
to the kernel log.

Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Adi Nissim <adin@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-31 15:35:37 -04:00
Huy Nguyen
df5f1361cc net/mlx5: Add pbmc and pptb in the port_access_reg_cap_mask
Add pbmc and pptb in the port_access_reg_cap_mask. These two
bits determine if device supports receive buffer configuration.

Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-05-24 14:23:33 -07:00
Ariel Levkovich
e818e255a5 IB/mlx5: Expose MPLS related tunneling offloads
This patch reports the device's capbilities to offload
encapsulated MPLS tunnel protocols to user-space:
- Capability to offload MPLS over GRE.
- Capability to offload MPLS over UDP.

Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-05-16 21:32:55 -06:00
Ariel Levkovich
71c6e8638c IB/mlx5: Add support for MPLS flow specification
This patch introduces support for the MPLS flow spec and
allows the creation of rules that are matching on the
MPLS label.

Applying the rule matching depends on the flow specs order and
the location of the MPLS in the spec list as there are different
configurations to be made in the device in the cases of MPLSoGRE
and MPLSoUDP vs. non-encapsulated MPLS.

Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-05-16 21:32:55 -06:00
Linus Torvalds
19fd08b85b Merge tag 'for-linus-unmerged' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull rdma updates from Jason Gunthorpe:
 "Doug and I are at a conference next week so if another PR is sent I
  expect it to only be bug fixes. Parav noted yesterday that there are
  some fringe case behavior changes in his work that he would like to
  fix, and I see that Intel has a number of rc looking patches for HFI1
  they posted yesterday.

  Parav is again the biggest contributor by patch count with his ongoing
  work to enable container support in the RDMA stack, followed by Leon
  doing syzkaller inspired cleanups, though most of the actual fixing
  went to RC.

  There is one uncomfortable series here fixing the user ABI to actually
  work as intended in 32 bit mode. There are lots of notes in the commit
  messages, but the basic summary is we don't think there is an actual
  32 bit kernel user of drivers/infiniband for several good reasons.

  However we are seeing people want to use a 32 bit user space with 64
  bit kernel, which didn't completely work today. So in fixing it we
  required a 32 bit rxe user to upgrade their userspace. rxe users are
  still already quite rare and we think a 32 bit one is non-existing.

   - Fix RDMA uapi headers to actually compile in userspace and be more
     complete

   - Three shared with netdev pull requests from Mellanox:

      * 7 patches, mostly to net with 1 IB related one at the back).
        This series addresses an IRQ performance issue (patch 1),
        cleanups related to the fix for the IRQ performance problem
        (patches 2-6), and then extends the fragmented completion queue
        support that already exists in the net side of the driver to the
        ib side of the driver (patch 7).

      * Mostly IB, with 5 patches to net that are needed to support the
        remaining 10 patches to the IB subsystem. This series extends
        the current 'representor' framework when the mlx5 driver is in
        switchdev mode from being a netdev only construct to being a
        netdev/IB dev construct. The IB dev is limited to raw Eth queue
        pairs only, but by having an IB dev of this type attached to the
        representor for a switchdev port, it enables DPDK to work on the
        switchdev device.

      * All net related, but needed as infrastructure for the rdma
        driver

   - Updates for the hns, i40iw, bnxt_re, cxgb3, cxgb4, hns drivers

   - SRP performance updates

   - IB uverbs write path cleanup patch series from Leon

   - Add RDMA_CM support to ib_srpt. This is disabled by default. Users
     need to set the port for ib_srpt to listen on in configfs in order
     for it to be enabled
     (/sys/kernel/config/target/srpt/discovery_auth/rdma_cm_port)

   - TSO and Scatter FCS support in mlx4

   - Refactor of modify_qp routine to resolve problems seen while
     working on new code that is forthcoming

   - More refactoring and updates of RDMA CM for containers support from
     Parav

   - mlx5 'fine grained packet pacing', 'ipsec offload' and 'device
     memory' user API features

   - Infrastructure updates for the new IOCTL interface, based on
     increased usage

   - ABI compatibility bug fixes to fully support 32 bit userspace on 64
     bit kernel as was originally intended. See the commit messages for
     extensive details

   - Syzkaller bugs and code cleanups motivated by them"

* tag 'for-linus-unmerged' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (199 commits)
  IB/rxe: Fix for oops in rxe_register_device on ppc64le arch
  IB/mlx5: Device memory mr registration support
  net/mlx5: Mkey creation command adjustments
  IB/mlx5: Device memory support in mlx5_ib
  net/mlx5: Query device memory capabilities
  IB/uverbs: Add device memory registration ioctl support
  IB/uverbs: Add alloc/free dm uverbs ioctl support
  IB/uverbs: Add device memory capabilities reporting
  IB/uverbs: Expose device memory capabilities to user
  RDMA/qedr: Fix wmb usage in qedr
  IB/rxe: Removed GID add/del dummy routines
  RDMA/qedr: Zero stack memory before copying to user space
  IB/mlx5: Add ability to hash by IPSEC_SPI when creating a TIR
  IB/mlx5: Add information for querying IPsec capabilities
  IB/mlx5: Add IPsec support for egress and ingress
  {net,IB}/mlx5: Add ipsec helper
  IB/mlx5: Add modify_flow_action_esp verb
  IB/mlx5: Add implementation for create and destroy action_xfrm
  IB/uverbs: Introduce ESP steering match filter
  IB/uverbs: Add modify ESP flow_action
  ...
2018-04-06 17:35:43 -07:00
Ariel Levkovich
e72bd817ae net/mlx5: Query device memory capabilities
This patch adds querying of device memory capabilities by the mlx5_core
driver during initialization.

Device memory capabilities is a new capability type and structure
which contains the necessary data that is needed for future device
memory allocation.

The presence of this new capabilities struct is indicated in the
general capabilities struct which is queried first by the driver.
If the presence bit is set, the driver will also query the new
capabilities struct and save it in the device context.

Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-04-05 13:04:48 -06:00
Tariq Toukan
619a8f2a42 net/mlx5e: Use linear SKB in Striding RQ
Current Striding RQ HW feature utilizes the RX buffers so that
there is no wasted room between the strides. This maximises
the memory utilization.
This prevents the use of build_skb() (which requires headroom
and tailroom), and demands to memcpy the packets headers into
the skb linear part.

In this patch, whenever a set of conditions holds, we apply
an RQ configuration that allows combining the use of linear SKB
on top of a Striding RQ.

To use build_skb() with Striding RQ, the following must hold:
1. packet does not cross a page boundary.
2. there is enough headroom and tailroom surrounding the packet.

We can satisfy 1 and 2 by configuring:
	stride size = MTU + headroom + tailoom.

This is possible only when:
a. (MTU - headroom - tailoom) does not exceed PAGE_SIZE.
b. HW LRO is turned off.

Using linear SKB has many advantages:
- Saves a memcpy of the headers.
- No page-boundary checks in datapath.
- No filler CQEs.
- Significantly smaller CQ.
- SKB data continuously resides in linear part, and not split to
  small amount (linear part) and large amount (fragment).
  This saves datapath cycles in driver and improves utilization
  of SKB fragments in GRO.
- The fragments of a resulting GRO SKB follow the IP forwarding
  assumption of equal-size fragments.

Some implementation details:
HW writes the packets to the beginning of a stride,
i.e. does not keep headroom. To overcome this we make sure we can
extend backwards and use the last bytes of stride i-1.
Extra care is needed for stride 0 as it has no preceding stride.
We make sure headroom bytes are available by shifting the buffer
pointer passed to HW by headroom bytes.

This configuration now becomes default, whenever capable.
Of course, this implies turning LRO off.

Performance testing:
ConnectX-5, single core, single RX ring, default MTU.

UDP packet rate, early drop in TC layer:

--------------------------------------------
| pkt size | before    | after     | ratio |
--------------------------------------------
| 1500byte | 4.65 Mpps | 5.96 Mpps | 1.28x |
|  500byte | 5.23 Mpps | 5.97 Mpps | 1.14x |
|   64byte | 5.94 Mpps | 5.96 Mpps | 1.00x |
--------------------------------------------

TCP streams: ~20% gain

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2018-03-30 16:54:49 -07:00