Björn Töpel 7fd3253a7d net: Introduce preferred busy-polling ... 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 6f8b12d661 ("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> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/bpf/20201130185205.196029-2-bjorn.topel@gmail.com		2020-12-01 00:09:25 +01:00
..
apc.h
asi.h
auxvec.h
bitsperlong.h
byteorder.h
display7seg.h
envctrl.h
errno.h
fbio.h
fcntl.h
ioctl.h
ioctls.h	tty/serial_core: add ISO7816 infrastructure	2018-10-02 13:38:55 -07:00
ipcbuf.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc	2020-01-30 07:36:43 -08:00
Kbuild	treewide: Add SPDX license identifier - Kbuild	2019-05-30 11:32:33 -07:00
mman.h	mm/mmap: move common defines to mman-common.h	2019-07-16 19:23:25 -07:00
msgbuf.h	arch: msgbuf.h: make uapi asm/msgbuf.h self-contained	2019-12-04 19:44:14 -08:00
openpromio.h	sparc: fix unknown type name u_int in uapi header	2019-06-13 14:12:19 -07:00
oradax.h	treewide: add "WITH Linux-syscall-note" to SPDX tag of uapi headers	2019-07-25 11:05:10 +02:00
param.h
perfctr.h
poll.h
posix_types.h	arch: sparc: Override struct __kernel_old_timeval	2019-02-03 11:17:30 -08:00
psr.h
psrcompat.h
pstate.h
ptrace.h
resource.h
sembuf.h	arch: sembuf.h: make uapi asm/sembuf.h self-contained	2019-12-04 19:44:14 -08:00
setup.h
shmbuf.h	y2038: ipc: remove __kernel_time_t reference from headers	2019-11-15 14:38:28 +01:00
sigcontext.h
siginfo.h	signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE	2018-10-03 16:46:43 +02:00
signal.h
socket.h	net: Introduce preferred busy-polling	2020-12-01 00:09:25 +01:00
stat.h	y2038: stat: avoid 'time_t' in 'struct stat'	2019-11-15 14:38:28 +01:00
swab.h
termbits.h
termios.h
traps.h
uctx.h
unistd.h	sparc: generate uapi header and system call table files	2018-11-18 18:52:22 -08:00
utrap.h
watchdog.h