Introduce preferred busy-polling #351
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The existing busy-polling mode, enabled by the SO_BUSY_POLL socket option or system-wide using the /proc/sys/net/core/busy_read knob, is an opportunistic. That means that if the NAPI context is not scheduled, it will poll it. If, after busy-polling, the budget is exceeded the busy-polling logic will schedule the NAPI onto the regular softirq handling. One implication of the behavior above is that a busy/heavy loaded NAPI context will never enter/allow for busy-polling. Some applications prefer that most NAPI processing would be done by busy-polling. This series adds a new socket option, SO_PREFER_BUSY_POLL, that works in concert with the napi_defer_hard_irqs and gro_flush_timeout knobs. The napi_defer_hard_irqs and gro_flush_timeout knobs were introduced in commit 6f8b12d ("net: napi: add hard irqs deferral feature"), and allows for a user to defer interrupts to be enabled and instead schedule the NAPI context from a watchdog timer. When a user enables the SO_PREFER_BUSY_POLL, again with the other knobs enabled, and the NAPI context is being processed by a softirq, the softirq NAPI processing will exit early to allow the busy-polling to be performed. If the application stops performing busy-polling via a system call, the watchdog timer defined by gro_flush_timeout will timeout, and regular softirq handling will resume. In summary; Heavy traffic applications that prefer busy-polling over softirq processing should use this option. Example usage: $ echo 2 | sudo tee /sys/class/net/ens785f1/napi_defer_hard_irqs $ echo 200000 | sudo tee /sys/class/net/ens785f1/gro_flush_timeout Note that the timeout should be larger than the userspace processing window, otherwise the watchdog will timeout and fall back to regular softirq processing. Enable the SO_BUSY_POLL/SO_PREFER_BUSY_POLL options on your socket. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
This option lets a user set a per socket NAPI budget for busy-polling. If the options is not set, it will use the default of 8. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Add support for non-blocking recvmsg() to XDP sockets. Previously, only sendmsg() was supported by XDP socket. Now, for symmetry and the upcoming busy-polling support, recvmsg() is added. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Add a check for need wake up in sendmsg(), so that if a user calls
sendmsg() when no wakeup is needed, do not trigger a wakeup.
To simplify the need wakeup check in the syscall, unconditionally
enable the need wakeup flag for Tx. This has a side-effect for poll();
If poll() is called for a socket without enabled need wakeup, a Tx
wakeup is unconditionally performed.
The wakeup matrix for AF_XDP now looks like:
need wakeup | poll() | sendmsg() | recvmsg()
------------+--------------+-------------+------------
disabled | wake Tx | wake Tx | nop
enabled | check flag; | check flag; | check flag;
| wake Tx/Rx | wake Tx | wake Rx
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Wire-up XDP socket busy-poll support for recvmsg() and sendmsg(). If the XDP socket prefers busy-polling, make sure that no wakeup/IPI is performed. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Add napi_id to the xdp_rxq_info structure, and make sure the XDP socket pick up the napi_id in the Rx path. The napi_id is used to find the corresponding NAPI structure for socket busy polling. Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Acked-by: Tariq Toukan <tariqt@nvidia.com>
Start using recvfrom() the rxdrop scenario. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Start using recvfrom() the l2fwd scenario, instead of poll() which is more expensive and need additional knobs for busy-polling. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Add a new option to xdpsock, 'B', for busy-polling. This option will also set the batching size, 'b' option, to the busy-poll budget. Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Support for the SO_BUSY_POLL_BUDGET setsockopt, via the batching
option ('b').
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
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Master branch: 024cd2c |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=384961 expired. Closing PR. |
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Sep 16, 2023
Puranjay Mohan says: ==================== arm32, bpf: add support for cpuv4 insns Changes in V2 -> V3 - Added comments at places where there could be confustion. - In the patch for DIV64, fix the if-else case that would never run. - In the same patch use a single instruction to POP caller saved regs. - Add a patch to change maintainership of ARM32 BPF JIT. Changes in V1 -> V2: - Fix coding style issues. - Don't use tmp variable for src in emit_ldsx_r() as it is redundant. - Optimize emit_ldsx_r() when offset can fit in immediate. Add the support for cpuv4 instructions for ARM32 BPF JIT. 64-bit division was not supported earlier so this series adds 64-bit DIV, SDIV, MOD, SMOD instructions as well. This series needs any one of the patches from [1] to disable zero-extension for BPF_MEMSX to support ldsx. The relevant selftests have passed expect ldsx_insn which needs fentry: Tested on BeagleBone Black (ARMv7-A): [root@alarm del]# echo 1 > /proc/sys/net/core/bpf_jit_enable [root@alarm del]# ./test_progs -a verifier_sdiv,verifier_movsx,verifier_ldsx,verifier_gotol,verifier_bswap #337/1 verifier_bswap/BSWAP, 16:OK #337/2 verifier_bswap/BSWAP, 16 @unpriv:OK #337/3 verifier_bswap/BSWAP, 32:OK #337/4 verifier_bswap/BSWAP, 32 @unpriv:OK #337/5 verifier_bswap/BSWAP, 64:OK #337/6 verifier_bswap/BSWAP, 64 @unpriv:OK #337 verifier_bswap:OK #351/1 verifier_gotol/gotol, small_imm:OK #351/2 verifier_gotol/gotol, small_imm @unpriv:OK #351 verifier_gotol:OK #359/1 verifier_ldsx/LDSX, S8:OK #359/2 verifier_ldsx/LDSX, S8 @unpriv:OK #359/3 verifier_ldsx/LDSX, S16:OK #359/4 verifier_ldsx/LDSX, S16 @unpriv:OK #359/5 verifier_ldsx/LDSX, S32:OK #359/6 verifier_ldsx/LDSX, S32 @unpriv:OK #359/7 verifier_ldsx/LDSX, S8 range checking, privileged:OK #359/8 verifier_ldsx/LDSX, S16 range checking:OK #359/9 verifier_ldsx/LDSX, S16 range checking @unpriv:OK #359/10 verifier_ldsx/LDSX, S32 range checking:OK #359/11 verifier_ldsx/LDSX, S32 range checking @unpriv:OK #359 verifier_ldsx:OK #370/1 verifier_movsx/MOV32SX, S8:OK #370/2 verifier_movsx/MOV32SX, S8 @unpriv:OK #370/3 verifier_movsx/MOV32SX, S16:OK #370/4 verifier_movsx/MOV32SX, S16 @unpriv:OK #370/5 verifier_movsx/MOV64SX, S8:OK #370/6 verifier_movsx/MOV64SX, S8 @unpriv:OK #370/7 verifier_movsx/MOV64SX, S16:OK #370/8 verifier_movsx/MOV64SX, S16 @unpriv:OK #370/9 verifier_movsx/MOV64SX, S32:OK #370/10 verifier_movsx/MOV64SX, S32 @unpriv:OK #370/11 verifier_movsx/MOV32SX, S8, range_check:OK #370/12 verifier_movsx/MOV32SX, S8, range_check @unpriv:OK #370/13 verifier_movsx/MOV32SX, S16, range_check:OK #370/14 verifier_movsx/MOV32SX, S16, range_check @unpriv:OK #370/15 verifier_movsx/MOV32SX, S16, range_check 2:OK #370/16 verifier_movsx/MOV32SX, S16, range_check 2 @unpriv:OK #370/17 verifier_movsx/MOV64SX, S8, range_check:OK #370/18 verifier_movsx/MOV64SX, S8, range_check @unpriv:OK #370/19 verifier_movsx/MOV64SX, S16, range_check:OK #370/20 verifier_movsx/MOV64SX, S16, range_check @unpriv:OK #370/21 verifier_movsx/MOV64SX, S32, range_check:OK #370/22 verifier_movsx/MOV64SX, S32, range_check @unpriv:OK #370/23 verifier_movsx/MOV64SX, S16, R10 Sign Extension:OK #370/24 verifier_movsx/MOV64SX, S16, R10 Sign Extension @unpriv:OK #370 verifier_movsx:OK #382/1 verifier_sdiv/SDIV32, non-zero imm divisor, check 1:OK #382/2 verifier_sdiv/SDIV32, non-zero imm divisor, check 1 @unpriv:OK #382/3 verifier_sdiv/SDIV32, non-zero imm divisor, check 2:OK #382/4 verifier_sdiv/SDIV32, non-zero imm divisor, check 2 @unpriv:OK #382/5 verifier_sdiv/SDIV32, non-zero imm divisor, check 3:OK #382/6 verifier_sdiv/SDIV32, non-zero imm divisor, check 3 @unpriv:OK #382/7 verifier_sdiv/SDIV32, non-zero imm divisor, check 4:OK #382/8 verifier_sdiv/SDIV32, non-zero imm divisor, check 4 @unpriv:OK #382/9 verifier_sdiv/SDIV32, non-zero imm divisor, check 5:OK #382/10 verifier_sdiv/SDIV32, non-zero imm divisor, check 5 @unpriv:OK #382/11 verifier_sdiv/SDIV32, non-zero imm divisor, check 6:OK #382/12 verifier_sdiv/SDIV32, non-zero imm divisor, check 6 @unpriv:OK #382/13 verifier_sdiv/SDIV32, non-zero imm divisor, check 7:OK #382/14 verifier_sdiv/SDIV32, non-zero imm divisor, check 7 @unpriv:OK #382/15 verifier_sdiv/SDIV32, non-zero imm divisor, check 8:OK #382/16 verifier_sdiv/SDIV32, non-zero imm divisor, check 8 @unpriv:OK #382/17 verifier_sdiv/SDIV32, non-zero reg divisor, check 1:OK #382/18 verifier_sdiv/SDIV32, non-zero reg divisor, check 1 @unpriv:OK #382/19 verifier_sdiv/SDIV32, non-zero reg divisor, check 2:OK #382/20 verifier_sdiv/SDIV32, non-zero reg divisor, check 2 @unpriv:OK #382/21 verifier_sdiv/SDIV32, non-zero reg divisor, check 3:OK #382/22 verifier_sdiv/SDIV32, non-zero reg divisor, check 3 @unpriv:OK #382/23 verifier_sdiv/SDIV32, non-zero reg divisor, check 4:OK #382/24 verifier_sdiv/SDIV32, non-zero reg divisor, check 4 @unpriv:OK #382/25 verifier_sdiv/SDIV32, non-zero reg divisor, check 5:OK #382/26 verifier_sdiv/SDIV32, non-zero reg divisor, check 5 @unpriv:OK #382/27 verifier_sdiv/SDIV32, non-zero reg divisor, check 6:OK #382/28 verifier_sdiv/SDIV32, non-zero reg divisor, check 6 @unpriv:OK #382/29 verifier_sdiv/SDIV32, non-zero reg divisor, check 7:OK #382/30 verifier_sdiv/SDIV32, non-zero reg divisor, check 7 @unpriv:OK #382/31 verifier_sdiv/SDIV32, non-zero reg divisor, check 8:OK #382/32 verifier_sdiv/SDIV32, non-zero reg divisor, check 8 @unpriv:OK #382/33 verifier_sdiv/SDIV64, non-zero imm divisor, check 1:OK #382/34 verifier_sdiv/SDIV64, non-zero imm divisor, check 1 @unpriv:OK #382/35 verifier_sdiv/SDIV64, non-zero imm divisor, check 2:OK #382/36 verifier_sdiv/SDIV64, non-zero imm divisor, check 2 @unpriv:OK #382/37 verifier_sdiv/SDIV64, non-zero imm divisor, check 3:OK #382/38 verifier_sdiv/SDIV64, non-zero imm divisor, check 3 @unpriv:OK #382/39 verifier_sdiv/SDIV64, non-zero imm divisor, check 4:OK #382/40 verifier_sdiv/SDIV64, non-zero imm divisor, check 4 @unpriv:OK #382/41 verifier_sdiv/SDIV64, non-zero imm divisor, check 5:OK #382/42 verifier_sdiv/SDIV64, non-zero imm divisor, check 5 @unpriv:OK #382/43 verifier_sdiv/SDIV64, non-zero imm divisor, check 6:OK #382/44 verifier_sdiv/SDIV64, non-zero imm divisor, check 6 @unpriv:OK #382/45 verifier_sdiv/SDIV64, non-zero reg divisor, check 1:OK #382/46 verifier_sdiv/SDIV64, non-zero reg divisor, check 1 @unpriv:OK #382/47 verifier_sdiv/SDIV64, non-zero reg divisor, check 2:OK #382/48 verifier_sdiv/SDIV64, non-zero reg divisor, check 2 @unpriv:OK #382/49 verifier_sdiv/SDIV64, non-zero reg divisor, check 3:OK #382/50 verifier_sdiv/SDIV64, non-zero reg divisor, check 3 @unpriv:OK #382/51 verifier_sdiv/SDIV64, non-zero reg divisor, check 4:OK #382/52 verifier_sdiv/SDIV64, non-zero reg divisor, check 4 @unpriv:OK #382/53 verifier_sdiv/SDIV64, non-zero reg divisor, check 5:OK #382/54 verifier_sdiv/SDIV64, non-zero reg divisor, check 5 @unpriv:OK #382/55 verifier_sdiv/SDIV64, non-zero reg divisor, check 6:OK #382/56 verifier_sdiv/SDIV64, non-zero reg divisor, check 6 @unpriv:OK #382/57 verifier_sdiv/SMOD32, non-zero imm divisor, check 1:OK #382/58 verifier_sdiv/SMOD32, non-zero imm divisor, check 1 @unpriv:OK #382/59 verifier_sdiv/SMOD32, non-zero imm divisor, check 2:OK #382/60 verifier_sdiv/SMOD32, non-zero imm divisor, check 2 @unpriv:OK #382/61 verifier_sdiv/SMOD32, non-zero imm divisor, check 3:OK #382/62 verifier_sdiv/SMOD32, non-zero imm divisor, check 3 @unpriv:OK #382/63 verifier_sdiv/SMOD32, non-zero imm divisor, check 4:OK #382/64 verifier_sdiv/SMOD32, non-zero imm divisor, check 4 @unpriv:OK #382/65 verifier_sdiv/SMOD32, non-zero imm divisor, check 5:OK #382/66 verifier_sdiv/SMOD32, non-zero imm divisor, check 5 @unpriv:OK #382/67 verifier_sdiv/SMOD32, non-zero imm divisor, check 6:OK #382/68 verifier_sdiv/SMOD32, non-zero imm divisor, check 6 @unpriv:OK #382/69 verifier_sdiv/SMOD32, non-zero reg divisor, check 1:OK #382/70 verifier_sdiv/SMOD32, non-zero reg divisor, check 1 @unpriv:OK #382/71 verifier_sdiv/SMOD32, non-zero reg divisor, check 2:OK #382/72 verifier_sdiv/SMOD32, non-zero reg divisor, check 2 @unpriv:OK #382/73 verifier_sdiv/SMOD32, non-zero reg divisor, check 3:OK #382/74 verifier_sdiv/SMOD32, non-zero reg divisor, check 3 @unpriv:OK #382/75 verifier_sdiv/SMOD32, non-zero reg divisor, check 4:OK #382/76 verifier_sdiv/SMOD32, non-zero reg divisor, check 4 @unpriv:OK #382/77 verifier_sdiv/SMOD32, non-zero reg divisor, check 5:OK #382/78 verifier_sdiv/SMOD32, non-zero reg divisor, check 5 @unpriv:OK #382/79 verifier_sdiv/SMOD32, non-zero reg divisor, check 6:OK #382/80 verifier_sdiv/SMOD32, non-zero reg divisor, check 6 @unpriv:OK #382/81 verifier_sdiv/SMOD64, non-zero imm divisor, check 1:OK #382/82 verifier_sdiv/SMOD64, non-zero imm divisor, check 1 @unpriv:OK #382/83 verifier_sdiv/SMOD64, non-zero imm divisor, check 2:OK #382/84 verifier_sdiv/SMOD64, non-zero imm divisor, check 2 @unpriv:OK #382/85 verifier_sdiv/SMOD64, non-zero imm divisor, check 3:OK #382/86 verifier_sdiv/SMOD64, non-zero imm divisor, check 3 @unpriv:OK #382/87 verifier_sdiv/SMOD64, non-zero imm divisor, check 4:OK #382/88 verifier_sdiv/SMOD64, non-zero imm divisor, check 4 @unpriv:OK #382/89 verifier_sdiv/SMOD64, non-zero imm divisor, check 5:OK #382/90 verifier_sdiv/SMOD64, non-zero imm divisor, check 5 @unpriv:OK #382/91 verifier_sdiv/SMOD64, non-zero imm divisor, check 6:OK #382/92 verifier_sdiv/SMOD64, non-zero imm divisor, check 6 @unpriv:OK #382/93 verifier_sdiv/SMOD64, non-zero imm divisor, check 7:OK #382/94 verifier_sdiv/SMOD64, non-zero imm divisor, check 7 @unpriv:OK #382/95 verifier_sdiv/SMOD64, non-zero imm divisor, check 8:OK #382/96 verifier_sdiv/SMOD64, non-zero imm divisor, check 8 @unpriv:OK #382/97 verifier_sdiv/SMOD64, non-zero reg divisor, check 1:OK #382/98 verifier_sdiv/SMOD64, non-zero reg divisor, check 1 @unpriv:OK #382/99 verifier_sdiv/SMOD64, non-zero reg divisor, check 2:OK #382/100 verifier_sdiv/SMOD64, non-zero reg divisor, check 2 @unpriv:OK #382/101 verifier_sdiv/SMOD64, non-zero reg divisor, check 3:OK #382/102 verifier_sdiv/SMOD64, non-zero reg divisor, check 3 @unpriv:OK #382/103 verifier_sdiv/SMOD64, non-zero reg divisor, check 4:OK #382/104 verifier_sdiv/SMOD64, non-zero reg divisor, check 4 @unpriv:OK #382/105 verifier_sdiv/SMOD64, non-zero reg divisor, check 5:OK #382/106 verifier_sdiv/SMOD64, non-zero reg divisor, check 5 @unpriv:OK #382/107 verifier_sdiv/SMOD64, non-zero reg divisor, check 6:OK #382/108 verifier_sdiv/SMOD64, non-zero reg divisor, check 6 @unpriv:OK #382/109 verifier_sdiv/SMOD64, non-zero reg divisor, check 7:OK #382/110 verifier_sdiv/SMOD64, non-zero reg divisor, check 7 @unpriv:OK #382/111 verifier_sdiv/SMOD64, non-zero reg divisor, check 8:OK #382/112 verifier_sdiv/SMOD64, non-zero reg divisor, check 8 @unpriv:OK #382/113 verifier_sdiv/SDIV32, zero divisor:OK #382/114 verifier_sdiv/SDIV32, zero divisor @unpriv:OK #382/115 verifier_sdiv/SDIV64, zero divisor:OK #382/116 verifier_sdiv/SDIV64, zero divisor @unpriv:OK #382/117 verifier_sdiv/SMOD32, zero divisor:OK #382/118 verifier_sdiv/SMOD32, zero divisor @unpriv:OK #382/119 verifier_sdiv/SMOD64, zero divisor:OK #382/120 verifier_sdiv/SMOD64, zero divisor @unpriv:OK #382 verifier_sdiv:OK Summary: 5/163 PASSED, 0 SKIPPED, 0 FAILED As the selftests don't compile for 32-bit architectures without modifications due to long being 32-bit, I have added new tests to lib/test_bpf.c for cpuv4 insns, all are passing: test_bpf: Summary: 1052 PASSED, 0 FAILED, [891/1040 JIT'ed] test_bpf: test_tail_calls: Summary: 10 PASSED, 0 FAILED, [10/10 JIT'ed] test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED [1] https://lore.kernel.org/all/mb61p5y4u3ptd.fsf@amazon.com/ ==================== Link: https://lore.kernel.org/r/20230907230550.1417590-1-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Pull request for series with
subject: Introduce preferred busy-polling
version: 2
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=384961