kernel/linux.git/include/linux/dim.h, branch v6.19.11

dim: pass dim_sample to net_dim() by reference

2024-11-03T20:36:54+00:00

net_dim() is currently passed a struct dim_sample argument by value. struct dim_sample is 24 bytes. Since this is greater 16 bytes, x86-64 passes it on the stack. All callers have already initialized dim_sample on the stack, so passing it by value requires pushing a duplicated copy to the stack. Either witing to the stack and immediately reading it, or perhaps dereferencing addresses relative to the stack pointer in a chain of push instructions, seems to perform quite poorly. In a heavy TCP workload, mlx5e_handle_rx_dim() consumes 3% of CPU time, 94% of which is attributed to the first push instruction to copy dim_sample on the stack for the call to net_dim(): // Call ktime_get() 0.26 |4ead2: call 4ead7 // Pass the address of struct dim in %rdi |4ead7: lea 0x3d0(%rbx),%rdi // Set dim_sample.pkt_ctr |4eade: mov %r13d,0x8(%rsp) // Set dim_sample.byte_ctr |4eae3: mov %r12d,0xc(%rsp) // Set dim_sample.event_ctr 0.15 |4eae8: mov %bp,0x10(%rsp) // Duplicate dim_sample on the stack 94.16 |4eaed: push 0x10(%rsp) 2.79 |4eaf1: push 0x10(%rsp) 0.07 |4eaf5: push %rax // Call net_dim() 0.21 |4eaf6: call 4eafb To allow the caller to reuse the struct dim_sample already on the stack, pass the struct dim_sample by reference to net_dim(). Signed-off-by: Caleb Sander Mateos Reviewed-by: Vladimir Oltean Reviewed-by: Shannon Nelson Reviewed-by: Florian Fainelli Reviewed-by: Arthur Kiyanovski Reviewed-by: Louis Peens Link: https://patch.msgid.link/20241031002326.3426181-2-csander@purestorage.com Signed-off-by: Jakub Kicinski

dim: make dim_calc_stats() inputs const pointers

2024-11-03T20:35:57+00:00

Make the start and end arguments to dim_calc_stats() const pointers to clarify that the function does not modify their values. Signed-off-by: Caleb Sander Mateos Reviewed-by: Vladimir Oltean Reviewed-by: Florian Fainelli Reviewed-by: Arthur Kiyanovski Link: https://patch.msgid.link/20241031002326.3426181-1-csander@purestorage.com Signed-off-by: Jakub Kicinski

dim: add new interfaces for initialization and getting results

2024-06-26T00:15:06+00:00

DIM-related mode and work have been collected in one same place, so new interfaces are added to provide convenience. Signed-off-by: Heng Qi Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240621101353.107425-5-hengqi@linux.alibaba.com Signed-off-by: Jakub Kicinski

ethtool: provide customized dim profile management

2024-06-26T00:15:06+00:00

The NetDIM library, currently leveraged by an array of NICs, delivers excellent acceleration benefits. Nevertheless, NICs vary significantly in their dim profile list prerequisites. Specifically, virtio-net backends may present diverse sw or hw device implementation, making a one-size-fits-all parameter list impractical. On Alibaba Cloud, the virtio DPU's performance under the default DIM profile falls short of expectations, partly due to a mismatch in parameter configuration. I also noticed that ice/idpf/ena and other NICs have customized profilelist or placed some restrictions on dim capabilities. Motivated by this, I tried adding new params for "ethtool -C" that provides a per-device control to modify and access a device's interrupt parameters. Usage ======== The target NIC is named ethx. Assume that ethx only declares support for rx profile setting (with DIM_PROFILE_RX flag set in profile_flags) and supports modification of usec and pkt fields. 1. Query the currently customized list of the device $ ethtool -c ethx ... rx-profile: {.usec = 1, .pkts = 256, .comps = n/a,}, {.usec = 8, .pkts = 256, .comps = n/a,}, {.usec = 64, .pkts = 256, .comps = n/a,}, {.usec = 128, .pkts = 256, .comps = n/a,}, {.usec = 256, .pkts = 256, .comps = n/a,} tx-profile: n/a 2. Tune $ ethtool -C ethx rx-profile 1,1,n_2,n,n_3,3,n_4,4,n_n,5,n "n" means do not modify this field. $ ethtool -c ethx ... rx-profile: {.usec = 1, .pkts = 1, .comps = n/a,}, {.usec = 2, .pkts = 256, .comps = n/a,}, {.usec = 3, .pkts = 3, .comps = n/a,}, {.usec = 4, .pkts = 4, .comps = n/a,}, {.usec = 256, .pkts = 5, .comps = n/a,} tx-profile: n/a 3. Hint If the device does not support some type of customized dim profiles, the corresponding "n/a" will display. If the "n/a" field is being modified, -EOPNOTSUPP will be reported. Signed-off-by: Heng Qi Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240621101353.107425-4-hengqi@linux.alibaba.com Signed-off-by: Jakub Kicinski

linux/dim: move useful macros to .h file

2024-06-26T00:15:06+00:00

Useful macros will be used effectively elsewhere. These will be utilized in subsequent patches. Signed-off-by: Heng Qi Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240621101353.107425-2-hengqi@linux.alibaba.com Signed-off-by: Jakub Kicinski

linux/dim: Do nothing if no time delta between samples

2023-05-09T09:06:45+00:00

Add return value for dim_calc_stats. This is an indication for the caller if curr_stats was assigned by the function. Avoid using curr_stats uninitialized over {rdma/net}_dim, when no time delta between samples. Coverity reported this potential use of an uninitialized variable. Fixes: 4c4dbb4a7363 ("net/mlx5e: Move dynamic interrupt coalescing code to include/linux") Fixes: cb3c7fd4f839 ("net/mlx5e: Support adaptive RX coalescing") Signed-off-by: Roy Novich Reviewed-by: Aya Levin Reviewed-by: Saeed Mahameed Signed-off-by: Tariq Toukan Reviewed-by: Leon Romanovsky Reviewed-by: Michal Kubiak Link: https://lore.kernel.org/r/20230507135743.138993-1-tariqt@nvidia.com Signed-off-by: Paolo Abeni

linux/dim: Fix divide by 0 in RDMA DIM

2022-06-28T13:37:25+00:00

Fix a divide 0 error in rdma_dim_stats_compare() when prev->cpe_ratio == 0. CallTrace: Hardware name: H3C R4900 G3/RS33M2C9S, BIOS 2.00.37P21 03/12/2020 task: ffff880194b78000 task.stack: ffffc90006714000 RIP: 0010:backport_rdma_dim+0x10e/0x240 [mlx_compat] RSP: 0018:ffff880c10e83ec0 EFLAGS: 00010202 RAX: 0000000000002710 RBX: ffff88096cd7f780 RCX: 0000000000000064 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 000000001d7c6c09 R13: ffff88096cd7f780 R14: ffff880b174fe800 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff880c10e80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000a0965b00 CR3: 000000000200a003 CR4: 00000000007606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ib_poll_handler+0x43/0x80 [ib_core] irq_poll_softirq+0xae/0x110 __do_softirq+0xd1/0x28c irq_exit+0xde/0xf0 do_IRQ+0x54/0xe0 common_interrupt+0x8f/0x8f ? cpuidle_enter_state+0xd9/0x2a0 ? cpuidle_enter_state+0xc7/0x2a0 ? do_idle+0x170/0x1d0 ? cpu_startup_entry+0x6f/0x80 ? start_secondary+0x1b9/0x210 ? secondary_startup_64+0xa5/0xb0 Code: 0f 87 e1 00 00 00 8b 4c 24 14 44 8b 43 14 89 c8 4d 63 c8 44 29 c0 99 31 d0 29 d0 31 d2 48 98 48 8d 04 80 48 8d 04 80 48 c1 e0 02 <49> f7 f1 48 83 f8 0a 0f 86 c1 00 00 00 44 39 c1 7f 10 48 89 df RIP: backport_rdma_dim+0x10e/0x240 [mlx_compat] RSP: ffff880c10e83ec0 Fixes: f4915455dcf0 ("linux/dim: Implement RDMA adaptive moderation (DIM)") Link: https://lore.kernel.org/r/20220627140004.3099-1-thomas.liu@ucloud.cn Signed-off-by: Tao Liu Reviewed-by: Max Gurtovoy Acked-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe

DIM: fix dim.h kernel-doc and headers

2019-10-10T02:33:43+00:00

Lots of fixes to kernel-doc in structs, enums, and functions. Also add header files that are being used but not yet #included. Signed-off-by: Randy Dunlap Cc: Yamin Friedman Cc: Tal Gilboa Cc: Saeed Mahameed Cc: Doug Ledford Cc: Jason Gunthorpe Cc: linux-rdma@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Jakub Kicinski

lib/dim: Fix -Wunused-const-variable warnings

2019-07-25T18:34:39+00:00

DIM causes to the following warnings during kernel compilation which indicates that tx_profile and rx_profile are supposed to be declared in *.c and not in *.h files. In file included from ./include/rdma/ib_verbs.h:64, from ./include/linux/mlx5/device.h:37, from ./include/linux/mlx5/driver.h:51, from ./include/linux/mlx5/vport.h:36, from drivers/infiniband/hw/mlx5/ib_virt.c:34: ./include/linux/dim.h:326:1: warning: _tx_profile_ defined but not used [-Wunused-const-variable=] 326 | tx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = { | ^~~~~~~~~~ ./include/linux/dim.h:320:1: warning: _rx_profile_ defined but not used [-Wunused-const-variable=] 320 | rx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = { | ^~~~~~~~~~ Fixes: 4f75da3666c0 ("linux/dim: Move implementation to .c files") Signed-off-by: Leon Romanovsky Reviewed-by: Bart Van Assche Acked-by: Saeed Mahameed Signed-off-by: David S. Miller

RDMA/core: Fix -Wunused-const-variable warnings

2019-07-11T14:49:55+00:00

The commit below introduced a few compilation warnings. In file included from ./include/rdma/ib_verbs.h:64, from ./include/linux/mlx5/device.h:37, from ./include/linux/mlx5/driver.h:51, from drivers/net/ethernet/mellanox/mlx5/core/uar.c:36: ./include/linux/dim.h:378:1: warning: 'rdma_dim_prof' defined but not used [-Wunused-const-variable=] rdma_dim_prof[RDMA_DIM_PARAMS_NUM_PROFILES] = { ^~~~~~~~~~~~~ In file included from ./include/rdma/ib_verbs.h:64, from ./include/linux/mlx5/device.h:37, from ./include/linux/mlx5/driver.h:51, from drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c:37: ./include/linux/dim.h:378:1: warning: 'rdma_dim_prof' defined but not used [-Wunused-const-variable=] rdma_dim_prof[RDMA_DIM_PARAMS_NUM_PROFILES] = { ^~~~~~~~~~~~~ Since only ib_cq_rdma_dim_work() in drivers/infiniband/core/cq.c uses it, just move the definition over there. Fixes: f4915455dcf0 ("linux/dim: Implement RDMA adaptive moderation (DIM)") Signed-off-by: Qian Cai Reviewed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe