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66aa0678ef
Current largesend and checksum offload feature in ibmveth driver,
- Source VM sends the TCP packets with ip_summed field set as
CHECKSUM_PARTIAL and TCP pseudo header checksum is placed in
checksum field
- CHECKSUM_PARTIAL flag in SKB will enable ibmveth driver to mark
"no checksum" and "checksum good" bits in transmit buffer descriptor
before the packet is delivered to pseries PowerVM Hypervisor
- If ibmveth has largesend capability enabled, transmit buffer descriptors
are market accordingly before packet is delivered to Hypervisor
(along with mss value for packets with length > MSS)
- Destination VM's ibmveth driver receives the packet with "checksum good"
bit set and so, SKB's ip_summed field is set with CHECKSUM_UNNECESSARY
- If "largesend" bit was on, mss value is copied from receive descriptor
into SKB's gso_size and other flags are appropriately set for
packets > MSS size
- The packet is now successfully delivered up the stack in destination VM
The offloads described above works fine for TCP communication among VMs in
the same pseries server ( VM A <=> PowerVM Hypervisor <=> VM B )
We are now enabling support for OVS in pseries PowerVM environment. One of
our requirements is to have ibmveth driver configured in "Trunk" mode, when
they are used with OVS. This is because, PowerVM Hypervisor will no more
bridge the packets between VMs, instead the packets are delivered to
IO Server which hosts OVS to bridge them between VMs or to external
networks (flow shown below),
VM A <=> PowerVM Hypervisor <=> IO Server(OVS) <=> PowerVM Hypervisor
<=> VM B
In "IO server" the packet is received by inbound Trunk ibmveth and then
delivered to OVS, which is then bridged to outbound Trunk ibmveth (shown
below),
Inbound Trunk ibmveth <=> OVS <=> Outbound Trunk ibmveth
In this model, we hit the following issues which impacted the VM
communication performance,
- Issue 1: ibmveth doesn't support largesend and checksum offload features
when configured as "Trunk". Driver has explicit checks to prevent
enabling these offloads.
- Issue 2: SYN packet drops seen at destination VM. When the packet
originates, it has CHECKSUM_PARTIAL flag set and as it gets delivered to
IO server's inbound Trunk ibmveth, on validating "checksum good" bits
in ibmveth receive routine, SKB's ip_summed field is set with
CHECKSUM_UNNECESSARY flag. This packet is then bridged by OVS (or Linux
Bridge) and delivered to outbound Trunk ibmveth. At this point the
outbound ibmveth transmit routine will not set "no checksum" and
"checksum good" bits in transmit buffer descriptor, as it does so only
when the ip_summed field is CHECKSUM_PARTIAL. When this packet gets
delivered to destination VM, TCP layer receives the packet with checksum
value of 0 and with no checksum related flags in ip_summed field. This
leads to packet drops. So, TCP connections never goes through fine.
- Issue 3: First packet of a TCP connection will be dropped, if there is
no OVS flow cached in datapath. OVS while trying to identify the flow,
computes the checksum. The computed checksum will be invalid at the
receiving end, as ibmveth transmit routine zeroes out the pseudo
checksum value in the packet. This leads to packet drop.
- Issue 4: ibmveth driver doesn't have support for SKB's with frag_list.
When Physical NIC has GRO enabled and when OVS bridges these packets,
OVS vport send code will end up calling dev_queue_xmit, which in turn
calls validate_xmit_skb.
In validate_xmit_skb routine, the larger packets will get segmented into
MSS sized segments, if SKB has a frag_list and if the driver to which
they are delivered to doesn't support NETIF_F_FRAGLIST feature.
This patch addresses the above four issues, thereby enabling end to end
largesend and checksum offload support for better performance.
- Fix for Issue 1 : Remove checks which prevent enabling TCP largesend and
checksum offloads.
- Fix for Issue 2 : When ibmveth receives a packet with "checksum good"
bit set and if its configured in Trunk mode, set appropriate SKB fields
using skb_partial_csum_set (ip_summed field is set with
CHECKSUM_PARTIAL)
- Fix for Issue 3: Recompute the pseudo header checksum before sending the
SKB up the stack.
- Fix for Issue 4: Linearize the SKBs with frag_list. Though we end up
allocating buffers and copying data, this fix gives
upto 4X throughput increase.
Note: All these fixes need to be dropped together as fixing just one of
them will lead to other issues immediately (especially for Issues 1,2 & 3).
Signed-off-by: Sivakumar Krishnasamy <ksiva@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
223 lines
6.8 KiB
C
223 lines
6.8 KiB
C
/*
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* IBM Power Virtual Ethernet Device Driver
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright (C) IBM Corporation, 2003, 2010
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*
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* Authors: Dave Larson <larson1@us.ibm.com>
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* Santiago Leon <santil@linux.vnet.ibm.com>
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* Brian King <brking@linux.vnet.ibm.com>
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* Robert Jennings <rcj@linux.vnet.ibm.com>
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* Anton Blanchard <anton@au.ibm.com>
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*/
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#ifndef _IBMVETH_H
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#define _IBMVETH_H
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/* constants for H_MULTICAST_CTRL */
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#define IbmVethMcastReceptionModifyBit 0x80000UL
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#define IbmVethMcastReceptionEnableBit 0x20000UL
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#define IbmVethMcastFilterModifyBit 0x40000UL
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#define IbmVethMcastFilterEnableBit 0x10000UL
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#define IbmVethMcastEnableRecv (IbmVethMcastReceptionModifyBit | IbmVethMcastReceptionEnableBit)
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#define IbmVethMcastDisableRecv (IbmVethMcastReceptionModifyBit)
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#define IbmVethMcastEnableFiltering (IbmVethMcastFilterModifyBit | IbmVethMcastFilterEnableBit)
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#define IbmVethMcastDisableFiltering (IbmVethMcastFilterModifyBit)
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#define IbmVethMcastAddFilter 0x1UL
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#define IbmVethMcastRemoveFilter 0x2UL
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#define IbmVethMcastClearFilterTable 0x3UL
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#define IBMVETH_ILLAN_LRG_SR_ENABLED 0x0000000000010000UL
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#define IBMVETH_ILLAN_LRG_SND_SUPPORT 0x0000000000008000UL
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#define IBMVETH_ILLAN_PADDED_PKT_CSUM 0x0000000000002000UL
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#define IBMVETH_ILLAN_TRUNK_PRI_MASK 0x0000000000000F00UL
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#define IBMVETH_ILLAN_IPV6_TCP_CSUM 0x0000000000000004UL
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#define IBMVETH_ILLAN_IPV4_TCP_CSUM 0x0000000000000002UL
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#define IBMVETH_ILLAN_ACTIVE_TRUNK 0x0000000000000001UL
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/* hcall macros */
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#define h_register_logical_lan(ua, buflst, rxq, fltlst, mac) \
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plpar_hcall_norets(H_REGISTER_LOGICAL_LAN, ua, buflst, rxq, fltlst, mac)
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#define h_free_logical_lan(ua) \
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plpar_hcall_norets(H_FREE_LOGICAL_LAN, ua)
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#define h_add_logical_lan_buffer(ua, buf) \
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plpar_hcall_norets(H_ADD_LOGICAL_LAN_BUFFER, ua, buf)
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static inline long h_send_logical_lan(unsigned long unit_address,
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unsigned long desc1, unsigned long desc2, unsigned long desc3,
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unsigned long desc4, unsigned long desc5, unsigned long desc6,
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unsigned long corellator_in, unsigned long *corellator_out,
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unsigned long mss, unsigned long large_send_support)
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{
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long rc;
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unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
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if (large_send_support)
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rc = plpar_hcall9(H_SEND_LOGICAL_LAN, retbuf, unit_address,
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desc1, desc2, desc3, desc4, desc5, desc6,
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corellator_in, mss);
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else
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rc = plpar_hcall9(H_SEND_LOGICAL_LAN, retbuf, unit_address,
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desc1, desc2, desc3, desc4, desc5, desc6,
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corellator_in);
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*corellator_out = retbuf[0];
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return rc;
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}
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static inline long h_illan_attributes(unsigned long unit_address,
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unsigned long reset_mask, unsigned long set_mask,
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unsigned long *ret_attributes)
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{
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long rc;
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unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
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rc = plpar_hcall(H_ILLAN_ATTRIBUTES, retbuf, unit_address,
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reset_mask, set_mask);
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*ret_attributes = retbuf[0];
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return rc;
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}
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#define h_multicast_ctrl(ua, cmd, mac) \
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plpar_hcall_norets(H_MULTICAST_CTRL, ua, cmd, mac)
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#define h_change_logical_lan_mac(ua, mac) \
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plpar_hcall_norets(H_CHANGE_LOGICAL_LAN_MAC, ua, mac)
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#define IBMVETH_NUM_BUFF_POOLS 5
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#define IBMVETH_IO_ENTITLEMENT_DEFAULT 4243456 /* MTU of 1500 needs 4.2Mb */
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#define IBMVETH_BUFF_OH 22 /* Overhead: 14 ethernet header + 8 opaque handle */
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#define IBMVETH_MIN_MTU 68
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#define IBMVETH_MAX_POOL_COUNT 4096
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#define IBMVETH_BUFF_LIST_SIZE 4096
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#define IBMVETH_FILT_LIST_SIZE 4096
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#define IBMVETH_MAX_BUF_SIZE (1024 * 128)
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static int pool_size[] = { 512, 1024 * 2, 1024 * 16, 1024 * 32, 1024 * 64 };
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static int pool_count[] = { 256, 512, 256, 256, 256 };
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static int pool_count_cmo[] = { 256, 512, 256, 256, 64 };
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static int pool_active[] = { 1, 1, 0, 0, 1};
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#define IBM_VETH_INVALID_MAP ((u16)0xffff)
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struct ibmveth_buff_pool {
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u32 size;
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u32 index;
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u32 buff_size;
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u32 threshold;
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atomic_t available;
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u32 consumer_index;
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u32 producer_index;
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u16 *free_map;
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dma_addr_t *dma_addr;
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struct sk_buff **skbuff;
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int active;
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struct kobject kobj;
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};
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struct ibmveth_rx_q {
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u64 index;
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u64 num_slots;
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u64 toggle;
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dma_addr_t queue_dma;
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u32 queue_len;
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struct ibmveth_rx_q_entry *queue_addr;
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};
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struct ibmveth_adapter {
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struct vio_dev *vdev;
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struct net_device *netdev;
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struct napi_struct napi;
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unsigned int mcastFilterSize;
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void * buffer_list_addr;
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void * filter_list_addr;
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dma_addr_t buffer_list_dma;
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dma_addr_t filter_list_dma;
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struct ibmveth_buff_pool rx_buff_pool[IBMVETH_NUM_BUFF_POOLS];
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struct ibmveth_rx_q rx_queue;
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int pool_config;
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int rx_csum;
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int large_send;
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bool is_active_trunk;
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void *bounce_buffer;
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dma_addr_t bounce_buffer_dma;
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u64 fw_ipv6_csum_support;
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u64 fw_ipv4_csum_support;
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u64 fw_large_send_support;
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/* adapter specific stats */
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u64 replenish_task_cycles;
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u64 replenish_no_mem;
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u64 replenish_add_buff_failure;
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u64 replenish_add_buff_success;
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u64 rx_invalid_buffer;
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u64 rx_no_buffer;
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u64 tx_map_failed;
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u64 tx_send_failed;
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u64 tx_large_packets;
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u64 rx_large_packets;
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};
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/*
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* We pass struct ibmveth_buf_desc_fields to the hypervisor in registers,
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* so we don't need to byteswap the two elements. However since we use
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* a union (ibmveth_buf_desc) to convert from the struct to a u64 we
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* do end up with endian specific ordering of the elements and that
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* needs correcting.
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*/
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struct ibmveth_buf_desc_fields {
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#ifdef __BIG_ENDIAN
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u32 flags_len;
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u32 address;
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#else
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u32 address;
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u32 flags_len;
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#endif
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#define IBMVETH_BUF_VALID 0x80000000
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#define IBMVETH_BUF_TOGGLE 0x40000000
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#define IBMVETH_BUF_LRG_SND 0x04000000
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#define IBMVETH_BUF_NO_CSUM 0x02000000
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#define IBMVETH_BUF_CSUM_GOOD 0x01000000
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#define IBMVETH_BUF_LEN_MASK 0x00FFFFFF
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};
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union ibmveth_buf_desc {
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u64 desc;
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struct ibmveth_buf_desc_fields fields;
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};
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struct ibmveth_rx_q_entry {
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__be32 flags_off;
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#define IBMVETH_RXQ_TOGGLE 0x80000000
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#define IBMVETH_RXQ_TOGGLE_SHIFT 31
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#define IBMVETH_RXQ_VALID 0x40000000
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#define IBMVETH_RXQ_LRG_PKT 0x04000000
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#define IBMVETH_RXQ_NO_CSUM 0x02000000
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#define IBMVETH_RXQ_CSUM_GOOD 0x01000000
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#define IBMVETH_RXQ_OFF_MASK 0x0000FFFF
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__be32 length;
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/* correlator is only used by the OS, no need to byte swap */
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u64 correlator;
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};
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#endif /* _IBMVETH_H */
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