Andrii Nakryiko 1d34cb886c uprobes: switch to RCU Tasks Trace flavor for better performance ...

[ Upstream commit 87195a1ee3 ]

This patch switches uprobes SRCU usage to RCU Tasks Trace flavor, which
is optimized for more lightweight and quick readers (at the expense of
slower writers, which for uprobes is a fine tradeof) and has better
performance and scalability with number of CPUs.

Similarly to baseline vs SRCU, we've benchmarked SRCU-based
implementation vs RCU Tasks Trace implementation.

SRCU
====
uprobe-nop      ( 1 cpus):    3.276 ± 0.005M/s  (  3.276M/s/cpu)
uprobe-nop      ( 2 cpus):    4.125 ± 0.002M/s  (  2.063M/s/cpu)
uprobe-nop      ( 4 cpus):    7.713 ± 0.002M/s  (  1.928M/s/cpu)
uprobe-nop      ( 8 cpus):    8.097 ± 0.006M/s  (  1.012M/s/cpu)
uprobe-nop      (16 cpus):    6.501 ± 0.056M/s  (  0.406M/s/cpu)
uprobe-nop      (32 cpus):    4.398 ± 0.084M/s  (  0.137M/s/cpu)
uprobe-nop      (64 cpus):    6.452 ± 0.000M/s  (  0.101M/s/cpu)

uretprobe-nop   ( 1 cpus):    2.055 ± 0.001M/s  (  2.055M/s/cpu)
uretprobe-nop   ( 2 cpus):    2.677 ± 0.000M/s  (  1.339M/s/cpu)
uretprobe-nop   ( 4 cpus):    4.561 ± 0.003M/s  (  1.140M/s/cpu)
uretprobe-nop   ( 8 cpus):    5.291 ± 0.002M/s  (  0.661M/s/cpu)
uretprobe-nop   (16 cpus):    5.065 ± 0.019M/s  (  0.317M/s/cpu)
uretprobe-nop   (32 cpus):    3.622 ± 0.003M/s  (  0.113M/s/cpu)
uretprobe-nop   (64 cpus):    3.723 ± 0.002M/s  (  0.058M/s/cpu)

RCU Tasks Trace
===============
uprobe-nop      ( 1 cpus):    3.396 ± 0.002M/s  (  3.396M/s/cpu)
uprobe-nop      ( 2 cpus):    4.271 ± 0.006M/s  (  2.135M/s/cpu)
uprobe-nop      ( 4 cpus):    8.499 ± 0.015M/s  (  2.125M/s/cpu)
uprobe-nop      ( 8 cpus):   10.355 ± 0.028M/s  (  1.294M/s/cpu)
uprobe-nop      (16 cpus):    7.615 ± 0.099M/s  (  0.476M/s/cpu)
uprobe-nop      (32 cpus):    4.430 ± 0.007M/s  (  0.138M/s/cpu)
uprobe-nop      (64 cpus):    6.887 ± 0.020M/s  (  0.108M/s/cpu)

uretprobe-nop   ( 1 cpus):    2.174 ± 0.001M/s  (  2.174M/s/cpu)
uretprobe-nop   ( 2 cpus):    2.853 ± 0.001M/s  (  1.426M/s/cpu)
uretprobe-nop   ( 4 cpus):    4.913 ± 0.002M/s  (  1.228M/s/cpu)
uretprobe-nop   ( 8 cpus):    5.883 ± 0.002M/s  (  0.735M/s/cpu)
uretprobe-nop   (16 cpus):    5.147 ± 0.001M/s  (  0.322M/s/cpu)
uretprobe-nop   (32 cpus):    3.738 ± 0.008M/s  (  0.117M/s/cpu)
uretprobe-nop   (64 cpus):    4.397 ± 0.002M/s  (  0.069M/s/cpu)

Peak throughput for uprobes increases from 8 mln/s to 10.3 mln/s
(+28%!), and for uretprobes from 5.3 mln/s to 5.8 mln/s (+11%), as we
have more work to do on uretprobes side.

Even single-thread (no contention) performance is slightly better: 3.276
mln/s to 3.396 mln/s (+3.5%) for uprobes, and 2.055 mln/s to 2.174 mln/s
(+5.8%) for uretprobes.

We also select TASKS_TRACE_RCU for UPROBES in Kconfig due to the new
dependency.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20240910174312.3646590-1-andrii@kernel.org
Stable-dep-of: a56a38fd91 ("uprobes: Fix incorrect lockdep condition in filter_chain()")
Signed-off-by: Sasha Levin <sashal@kernel.org>

2026-03-13 17:20:28 +01:00

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