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[v3,0/2] riscv: Add perf support to collect KVM guest statistics from host side

Message ID cover.1726126795.git.zhouquan@iscas.ac.cn (mailing list archive)
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Series riscv: Add perf support to collect KVM guest statistics from host side | expand

Message

Quan Zhou Sept. 12, 2024, 8 a.m. UTC
From: Quan Zhou <zhouquan@iscas.ac.cn>

Add basic guest support to RISC-V perf, enabling it to distinguish
whether PMU interrupts occur in the host or the guest, and then
collect some basic guest information from the host side
(guest os callchain is not supported for now).

Based on the x86/arm implementation, tested with kvm-riscv.
test env:
- host: qemu-9.0.0
- guest: qemu-9.0.0 --enable-kvm (only start one guest and run top)

-----------------------------------------
1) perf kvm top
./perf kvm --host --guest \
  --guestkallsyms=/root/repo/shared/kallsyms \
  --guestmodules=/root/repo/shared/modules top

PerfTop:      41 irqs/sec  kernel:97.6% us: 0.0% guest kernel: 0.0% guest us: 0.0% exact:  0.0% [250Hz cycles:P],  (all, 4 CPUs)
-------------------------------------------------------------------------------

    64.57%  [kernel]        [k] default_idle_call
     3.12%  [kernel]        [k] _raw_spin_unlock_irqrestore
     3.03%  [guest.kernel]  [g] mem_serial_out
     2.61%  [kernel]        [k] handle_softirqs
     2.32%  [kernel]        [k] do_trap_ecall_u
     1.71%  [kernel]        [k] _raw_spin_unlock_irq
     1.26%  [guest.kernel]  [g] do_raw_spin_lock
     1.25%  [kernel]        [k] finish_task_switch.isra.0
     1.16%  [kernel]        [k] do_idle
     0.77%  libc.so.6       [.] ioctl
     0.76%  [kernel]        [k] queue_work_on
     0.69%  [kernel]        [k] __local_bh_enable_ip
     0.67%  [guest.kernel]  [g] __noinstr_text_start
     0.64%  [guest.kernel]  [g] mem_serial_in
     0.41%  libc.so.6       [.] pthread_sigmask
     0.39%  [kernel]        [k] mem_cgroup_uncharge_skmem
     0.39%  [kernel]        [k] __might_resched
     0.39%  [guest.kernel]  [g] _nohz_idle_balance.isra.0
     0.37%  [kernel]        [k] sched_balance_update_blocked_averages
     0.34%  [kernel]        [k] sched_balance_rq

2) perf kvm record
./perf kvm --host --guest \
  --guestkallsyms=/root/repo/shared/kallsyms \
  --guestmodules=/root/repo/shared/modules record -a sleep 60

[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 1.292 MB perf.data.kvm (17990 samples) ]

3) perf kvm report (the data shown here is not complete)
./perf kvm --host --guest \
  --guestkallsyms=/root/repo/shared/kallsyms \
  --guestmodules=/root/repo/shared/modules report -i perf.data.kvm

# Total Lost Samples: 0
#
# Samples: 17K of event 'cycles:P'
# Event count (approx.): 269968947184
#
# Overhead  Command          Shared Object            Symbol                                        
# ........  ...............  .......................  ..............................................
#
    61.86%  swapper          [kernel.kallsyms]        [k] default_idle_call
     2.93%  :6463            [guest.kernel.kallsyms]  [g] do_raw_spin_lock
     2.82%  :6462            [guest.kernel.kallsyms]  [g] mem_serial_out
     2.11%  sshd             [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
     1.78%  :6462            [guest.kernel.kallsyms]  [g] do_raw_spin_lock
     1.37%  swapper          [kernel.kallsyms]        [k] handle_softirqs
     1.36%  swapper          [kernel.kallsyms]        [k] do_idle
     1.21%  sshd             [kernel.kallsyms]        [k] do_trap_ecall_u
     1.21%  sshd             [kernel.kallsyms]        [k] _raw_spin_unlock_irq
     1.11%  qemu-system-ris  [kernel.kallsyms]        [k] do_trap_ecall_u
     0.93%  qemu-system-ris  libc.so.6                [.] ioctl
     0.89%  sshd             [kernel.kallsyms]        [k] __local_bh_enable_ip
     0.77%  qemu-system-ris  [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
     0.68%  qemu-system-ris  [kernel.kallsyms]        [k] queue_work_on
     0.65%  sshd             [kernel.kallsyms]        [k] handle_softirqs
     0.44%  :6462            [guest.kernel.kallsyms]  [g] mem_serial_in
     0.42%  sshd             libc.so.6                [.] pthread_sigmask
     0.34%  :6462            [guest.kernel.kallsyms]  [g] serial8250_tx_chars
     0.30%  swapper          [kernel.kallsyms]        [k] finish_task_switch.isra.0
     0.29%  swapper          [kernel.kallsyms]        [k] sched_balance_rq
     0.29%  sshd             [kernel.kallsyms]        [k] __might_resched
     0.26%  swapper          [kernel.kallsyms]        [k] tick_nohz_idle_exit
     0.26%  swapper          [kernel.kallsyms]        [k] sched_balance_update_blocked_averages
     0.26%  swapper          [kernel.kallsyms]        [k] _nohz_idle_balance.isra.0
     0.24%  qemu-system-ris  [kernel.kallsyms]        [k] finish_task_switch.isra.0
     0.23%  :6462            [guest.kernel.kallsyms]  [g] __noinstr_text_start
     
---
Change since v2:
- Rebased on v6.11-rc7
- Keep the misc type consistent with other architectures
  as `unsigned long` (Andrew)
- Add the same comment for `kvm_arch_pmi_in_guest`
  as in arm64. (Andrew)

Change since v1:
- Rebased on v6.11-rc3
- Fix incorrect misc type (Andrew)

---
v1 link:
https://lore.kernel.org/all/cover.1721271251.git.zhouquan@iscas.ac.cn/
v2 link:
https://lore.kernel.org/all/cover.1723518282.git.zhouquan@iscas.ac.cn/

Quan Zhou (2):
  riscv: perf: add guest vs host distinction
  riscv: KVM: add basic support for host vs guest profiling

 arch/riscv/include/asm/kvm_host.h   | 10 ++++++++
 arch/riscv/include/asm/perf_event.h |  7 ++++++
 arch/riscv/kernel/perf_callchain.c  | 38 +++++++++++++++++++++++++++++
 arch/riscv/kvm/Kconfig              |  1 +
 arch/riscv/kvm/main.c               | 12 +++++++--
 arch/riscv/kvm/vcpu.c               |  7 ++++++
 6 files changed, 73 insertions(+), 2 deletions(-)


base-commit: da3ea35007d0af457a0afc87e84fddaebc4e0b63

Comments

Anup Patel Oct. 5, 2024, 11:06 a.m. UTC | #1
On Thu, Sep 12, 2024 at 1:30 PM <zhouquan@iscas.ac.cn> wrote:
>
> From: Quan Zhou <zhouquan@iscas.ac.cn>
>
> Add basic guest support to RISC-V perf, enabling it to distinguish
> whether PMU interrupts occur in the host or the guest, and then
> collect some basic guest information from the host side
> (guest os callchain is not supported for now).
>
> Based on the x86/arm implementation, tested with kvm-riscv.
> test env:
> - host: qemu-9.0.0
> - guest: qemu-9.0.0 --enable-kvm (only start one guest and run top)
>
> -----------------------------------------
> 1) perf kvm top
> ./perf kvm --host --guest \
>   --guestkallsyms=/root/repo/shared/kallsyms \
>   --guestmodules=/root/repo/shared/modules top
>
> PerfTop:      41 irqs/sec  kernel:97.6% us: 0.0% guest kernel: 0.0% guest us: 0.0% exact:  0.0% [250Hz cycles:P],  (all, 4 CPUs)
> -------------------------------------------------------------------------------
>
>     64.57%  [kernel]        [k] default_idle_call
>      3.12%  [kernel]        [k] _raw_spin_unlock_irqrestore
>      3.03%  [guest.kernel]  [g] mem_serial_out
>      2.61%  [kernel]        [k] handle_softirqs
>      2.32%  [kernel]        [k] do_trap_ecall_u
>      1.71%  [kernel]        [k] _raw_spin_unlock_irq
>      1.26%  [guest.kernel]  [g] do_raw_spin_lock
>      1.25%  [kernel]        [k] finish_task_switch.isra.0
>      1.16%  [kernel]        [k] do_idle
>      0.77%  libc.so.6       [.] ioctl
>      0.76%  [kernel]        [k] queue_work_on
>      0.69%  [kernel]        [k] __local_bh_enable_ip
>      0.67%  [guest.kernel]  [g] __noinstr_text_start
>      0.64%  [guest.kernel]  [g] mem_serial_in
>      0.41%  libc.so.6       [.] pthread_sigmask
>      0.39%  [kernel]        [k] mem_cgroup_uncharge_skmem
>      0.39%  [kernel]        [k] __might_resched
>      0.39%  [guest.kernel]  [g] _nohz_idle_balance.isra.0
>      0.37%  [kernel]        [k] sched_balance_update_blocked_averages
>      0.34%  [kernel]        [k] sched_balance_rq
>
> 2) perf kvm record
> ./perf kvm --host --guest \
>   --guestkallsyms=/root/repo/shared/kallsyms \
>   --guestmodules=/root/repo/shared/modules record -a sleep 60
>
> [ perf record: Woken up 3 times to write data ]
> [ perf record: Captured and wrote 1.292 MB perf.data.kvm (17990 samples) ]
>
> 3) perf kvm report (the data shown here is not complete)
> ./perf kvm --host --guest \
>   --guestkallsyms=/root/repo/shared/kallsyms \
>   --guestmodules=/root/repo/shared/modules report -i perf.data.kvm
>
> # Total Lost Samples: 0
> #
> # Samples: 17K of event 'cycles:P'
> # Event count (approx.): 269968947184
> #
> # Overhead  Command          Shared Object            Symbol
> # ........  ...............  .......................  ..............................................
> #
>     61.86%  swapper          [kernel.kallsyms]        [k] default_idle_call
>      2.93%  :6463            [guest.kernel.kallsyms]  [g] do_raw_spin_lock
>      2.82%  :6462            [guest.kernel.kallsyms]  [g] mem_serial_out
>      2.11%  sshd             [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
>      1.78%  :6462            [guest.kernel.kallsyms]  [g] do_raw_spin_lock
>      1.37%  swapper          [kernel.kallsyms]        [k] handle_softirqs
>      1.36%  swapper          [kernel.kallsyms]        [k] do_idle
>      1.21%  sshd             [kernel.kallsyms]        [k] do_trap_ecall_u
>      1.21%  sshd             [kernel.kallsyms]        [k] _raw_spin_unlock_irq
>      1.11%  qemu-system-ris  [kernel.kallsyms]        [k] do_trap_ecall_u
>      0.93%  qemu-system-ris  libc.so.6                [.] ioctl
>      0.89%  sshd             [kernel.kallsyms]        [k] __local_bh_enable_ip
>      0.77%  qemu-system-ris  [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
>      0.68%  qemu-system-ris  [kernel.kallsyms]        [k] queue_work_on
>      0.65%  sshd             [kernel.kallsyms]        [k] handle_softirqs
>      0.44%  :6462            [guest.kernel.kallsyms]  [g] mem_serial_in
>      0.42%  sshd             libc.so.6                [.] pthread_sigmask
>      0.34%  :6462            [guest.kernel.kallsyms]  [g] serial8250_tx_chars
>      0.30%  swapper          [kernel.kallsyms]        [k] finish_task_switch.isra.0
>      0.29%  swapper          [kernel.kallsyms]        [k] sched_balance_rq
>      0.29%  sshd             [kernel.kallsyms]        [k] __might_resched
>      0.26%  swapper          [kernel.kallsyms]        [k] tick_nohz_idle_exit
>      0.26%  swapper          [kernel.kallsyms]        [k] sched_balance_update_blocked_averages
>      0.26%  swapper          [kernel.kallsyms]        [k] _nohz_idle_balance.isra.0
>      0.24%  qemu-system-ris  [kernel.kallsyms]        [k] finish_task_switch.isra.0
>      0.23%  :6462            [guest.kernel.kallsyms]  [g] __noinstr_text_start
>
> ---
> Change since v2:
> - Rebased on v6.11-rc7
> - Keep the misc type consistent with other architectures
>   as `unsigned long` (Andrew)
> - Add the same comment for `kvm_arch_pmi_in_guest`
>   as in arm64. (Andrew)
>
> Change since v1:
> - Rebased on v6.11-rc3
> - Fix incorrect misc type (Andrew)
>
> ---
> v1 link:
> https://lore.kernel.org/all/cover.1721271251.git.zhouquan@iscas.ac.cn/
> v2 link:
> https://lore.kernel.org/all/cover.1723518282.git.zhouquan@iscas.ac.cn/
>
> Quan Zhou (2):
>   riscv: perf: add guest vs host distinction
>   riscv: KVM: add basic support for host vs guest profiling

Please rebase this series upon Linux-6.12-rcX and send another version.

Regards,
Anup

>
>  arch/riscv/include/asm/kvm_host.h   | 10 ++++++++
>  arch/riscv/include/asm/perf_event.h |  7 ++++++
>  arch/riscv/kernel/perf_callchain.c  | 38 +++++++++++++++++++++++++++++
>  arch/riscv/kvm/Kconfig              |  1 +
>  arch/riscv/kvm/main.c               | 12 +++++++--
>  arch/riscv/kvm/vcpu.c               |  7 ++++++
>  6 files changed, 73 insertions(+), 2 deletions(-)
>
>
> base-commit: da3ea35007d0af457a0afc87e84fddaebc4e0b63
> --
> 2.34.1
>