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uprobe: uretprobe speed up #6662

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uprobe: uretprobe speed up #6662

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kernel-patches-daemon-bpf[bot]
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Pull request for series with
subject: uprobe: uretprobe speed up
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809

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Upstream branch: 14bb1e8
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: 2a702c2
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: 2a720cc
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: 45a683b
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: 74c8edc
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: 50e4957
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: b9404f7
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: e478cf2
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=838809
version: 1

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Upstream branch: 2a24e24
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=840535
version: 1

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Upstream branch: c186ed1
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=840535
version: 1

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Upstream branch: ce09cbd
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=840535
version: 1

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Upstream branch: 15ea39a
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=840535
version: 1

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Upstream branch: c07b4bc
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=840535
version: 1

@olsajiri
uprobe: Add uretprobe syscall to speed up return probe
22d0734 
Adding uretprobe syscall instead of trap to speed up return probe.

At the moment the uretprobe setup/path is:

  - install entry uprobe

  - when the uprobe is hit, it overwrites probed function's return address
    on stack with address of the trampoline that contains breakpoint
    instruction

  - the breakpoint trap code handles the uretprobe consumers execution and
    jumps back to original return address

This patch replaces the above trampoline's breakpoint instruction with new
ureprobe syscall call. This syscall does exactly the same job as the trap
with some more extra work:

  - syscall trampoline must save original value for rax/r11/rcx registers
    on stack - rax is set to syscall number and r11/rcx are changed and
    used by syscall instruction

  - the syscall code reads the original values of those registers and
    restore those values in task's pt_regs area

Even with the extra registers handling code the having uretprobes handled
by syscalls shows speed improvement.

  On Intel (11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz)

  current:

    base           :   15.888 ± 0.033M/s
    uprobe-nop     :    3.016 ± 0.000M/s
    uprobe-push    :    2.832 ± 0.005M/s
    uprobe-ret     :    1.104 ± 0.000M/s
    uretprobe-nop  :    1.487 ± 0.000M/s
    uretprobe-push :    1.456 ± 0.000M/s
    uretprobe-ret  :    0.816 ± 0.001M/s

  with the fix:

    base           :   15.116 ± 0.045M/s
    uprobe-nop     :    3.001 ± 0.045M/s
    uprobe-push    :    2.831 ± 0.004M/s
    uprobe-ret     :    1.102 ± 0.001M/s
    uretprobe-nop  :    1.969 ± 0.001M/s  < 32% speedup
    uretprobe-push :    1.905 ± 0.004M/s  < 30% speedup
    uretprobe-ret  :    0.933 ± 0.002M/s  < 14% speedup

  On Amd (AMD Ryzen 7 5700U)

  current:

    base           :    5.105 ± 0.003M/s
    uprobe-nop     :    1.552 ± 0.002M/s
    uprobe-push    :    1.408 ± 0.003M/s
    uprobe-ret     :    0.827 ± 0.001M/s
    uretprobe-nop  :    0.779 ± 0.001M/s
    uretprobe-push :    0.750 ± 0.001M/s
    uretprobe-ret  :    0.539 ± 0.001M/s

  with the fix:

    base           :    5.119 ± 0.002M/s
    uprobe-nop     :    1.523 ± 0.003M/s
    uprobe-push    :    1.384 ± 0.003M/s
    uprobe-ret     :    0.826 ± 0.002M/s
    uretprobe-nop  :    0.866 ± 0.002M/s  < 11% speedup
    uretprobe-push :    0.826 ± 0.002M/s  < 10% speedup
    uretprobe-ret  :    0.581 ± 0.001M/s  <  7% speedup

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
selftests/bpf: Add uretprobe test for regs integrity
a4d65a4 
Add uretprobe test that compares register values before and
after the uretprobe is hit. It also compares the register
values seen from attached bpf program.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
selftests/bpf: Add uretprobe test for regs changes
722e6e0 
Adding test that creates uprobe consumer on uretprobe which changes some
of the registers. Making sure the changed registers are propagated to the
user space from the ureprobe trampoline on x86_64.

To be able to do this, adding support to bpf_testmod to create uprobe via
new attribute file:
  /sys/kernel/bpf_testmod_uprobe

This file is expecting file offset and creates related uprobe on current
process exe file and removes existing uprobe if offset is 0. The can be
only single uprobe at any time.

The uprobe has specific consumer that changes registers used in ureprobe
trampoline and which are later checked in the test.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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Upstream branch: 49b73fa
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=840535
version: 1

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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=840535 expired. Closing PR.

@kernel-patches-daemon-bpf kernel-patches-daemon-bpf bot deleted the series/836016=>bpf-next branch April 5, 2024 21:30
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