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[PW_SID:1081352] drivers/perf: riscv: do not restart throttled events after overflow#1770

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[PW_SID:1081352] drivers/perf: riscv: do not restart throttled events after overflow#1770
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@linux-riscv-bot linux-riscv-bot commented Apr 15, 2026

PR for series 1081352 applied to workflow__riscv__fixes

Name: drivers/perf: riscv: do not restart throttled events after overflow
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1081352
Version: 1

drivers/perf: riscv: do not restart throttled events after overflow
5c65b8e 
Perf core uses `event->hw.interrupts == MAX_INTERRUPTS` to keep
throttled events stopped until it explicitly unthrottles them later.

However, current RISC-V Perf/PMU system unconditionally restarts all the
counters at the end of overflow handler, which bypasses the perf core's
throttle mechanism. Therefore, an unreasonable small sampling period
such as `perf top -c 20` may cause an IRQ storm and eventually leads to
soft lockup.

Fix this by filtering the counter start/restart mask: do not restart
counters for events already marked as throttled by the perf core. This
retains the throttle effect and prevents interrupt storms in such
workloads.

Signed-off-by: Zhanpeng Zhang <zhangzhanpeng.jasper@bytedance.com>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 118.97 seconds
Result: ERROR
Output:

Full log:
W: Support for running offline not available (unshare: unshare failed: Operation not permitted)
I: config: PASS in 0:00:30.400679
I: default: FAIL in 0:01:22.352918
I: kernel: SKIP in 0:00:00.000008
I: xipkernel: SKIP in 0:00:00.000004
I: modules: FAIL in 0:00:00.071278
I: dtbs: PASS in 0:00:01.447710
I: dtbs-legacy: SKIP in 0:00:00.003334
I: debugkernel: SKIP in 0:00:00.000004
I: headers: PASS in 0:00:01.031569
I: build output in /build/tmp.RuFeNVpwpH
tuxmake --download-all-korg-gcc-toolchains --target-arch=riscv --kconfig=rv32_defconfig --toolchain=llvm --wrapper=ccache --environment=KBUILD_BUILD_TIMESTAMP=@1621270510 --environment=KBUILD_BUILD_USER=tuxmake --environment=KBUILD_BUILD_HOST=tuxmake --environment=KCFLAGS=-ffile-prefix-map=/build/tmp.RuFeNVpwpH/build/= --runtime=null --image=docker.io/tuxmake/riscv_clang CROSS_COMPILE=riscv64-linux- config default kernel xipkernel modules dtbs dtbs-legacy debugkernel headers
make --silent --keep-going --jobs=48 O=/build/tmp.RuFeNVpwpH/build ARCH=riscv CROSS_COMPILE=riscv64-linux- LLVM=1 'CC=ccache clang' 'HOSTCC=ccache clang' rv32_defconfig
make --silent --keep-going --jobs=48 O=/build/tmp.RuFeNVpwpH/build ARCH=riscv CROSS_COMPILE=riscv64-linux- LLVM=1 'CC=ccache clang' 'HOSTCC=ccache clang'
/build/tmpax261cl6/drivers/perf/riscv_pmu_sbi.c:65:33: error: use of undeclared identifier 'MAX_INTERRUPTS'
   65 |         return event->hw.interrupts == MAX_INTERRUPTS;
      |                                        ^
1 error generated.
make[5]: *** [/build/tmpax261cl6/scripts/Makefile.build:289: drivers/perf/riscv_pmu_sbi.o] Error 1
make[5]: Target 'drivers/perf/' not remade because of errors.
make[4]: *** [/build/tmpax261cl6/scripts/Makefile.build:548: drivers/perf] Error 2
make[4]: Target 'drivers/' not remade because of errors.
make[3]: *** [/build/tmpax261cl6/scripts/Makefile.build:548: drivers] Error 2
make[3]: Target './' not remade because of errors.
make[2]: *** [/build/tmpax261cl6/Makefile:2105: .] Error 2
make[2]: Target '__all' not remade because of errors.
make[1]: *** [/build/tmpax261cl6/Makefile:248: __sub-make] Error 2
make[1]: Target '__all' not remade because of errors.
make: *** [Makefile:248: __sub-make] Error 2
make: Target '__all' not remade because of errors.
rm -rf /build/tmp.RuFeNVpwpH/build/modinstall
make --silent --keep-going --jobs=48 O=/build/tmp.RuFeNVpwpH/build INSTALL_MOD_STRIP=1 INSTALL_MOD_PATH=/build/tmp.RuFeNVpwpH/build/modinstall ARCH=riscv CROSS_COMPILE=riscv64-linux- LLVM=1 'CC=ccache clang' 'HOSTCC=ccache clang' modules_install
make[3]: *** No rule to make target 'modules.order', needed by '/build/tmp.RuFeNVpwpH/build/modinstall/lib/modules/7.0.0-rc5-00015-g5c65b8e99b07/modules.order'.
make[3]: *** No rule to make target 'modules.builtin', needed by '/build/tmp.RuFeNVpwpH/build/modinstall/lib/modules/7.0.0-rc5-00015-g5c65b8e99b07/modules.builtin'.
make[3]: *** No rule to make target 'modules.builtin.modinfo', needed by '/build/tmp.RuFeNVpwpH/build/modinstall/lib/modules/7.0.0-rc5-00015-g5c65b8e99b07/modules.builtin.modinfo'.
make[3]: Target '__modinst' not remade because of errors.
make[2]: *** [/build/tmpax261cl6/Makefile:2011: modules_install] Error 2
make[1]: *** [/build/tmpax261cl6/Makefile:248: __sub-make] Error 2
make[1]: Target 'modules_install' not remade because of errors.
make: *** [Makefile:248: __sub-make] Error 2
make: Target 'modules_install' not remade because of errors.
make --silent --keep-going --jobs=48 O=/build/tmp.RuFeNVpwpH/build INSTALL_DTBS_PATH=/build/tmp.RuFeNVpwpH/build/dtbsinstall/dtbs ARCH=riscv CROSS_COMPILE=riscv64-linux- LLVM=1 'CC=ccache clang' 'HOSTCC=ccache clang' dtbs
rm -rf /build/tmp.RuFeNVpwpH/build/dtbsinstall
mkdir -p /build/tmp.RuFeNVpwpH/build/dtbsinstall/dtbs
make --silent --keep-going --jobs=48 O=/build/tmp.RuFeNVpwpH/build INSTALL_DTBS_PATH=/build/tmp.RuFeNVpwpH/build/dtbsinstall/dtbs ARCH=riscv CROSS_COMPILE=riscv64-linux- LLVM=1 'CC=ccache clang' 'HOSTCC=ccache clang' dtbs_install
tar --sort=name --owner=tuxmake:1000 --group=tuxmake:1000 --mtime=@1776225276 --clamp-mtime -caf /build/tmp.RuFeNVpwpH/build/dtbs.tar -C /build/tmp.RuFeNVpwpH/build/dtbsinstall dtbs
rm -rf /build/tmp.RuFeNVpwpH/build/install_hdr
make --silent --keep-going --jobs=48 O=/build/tmp.RuFeNVpwpH/build INSTALL_HDR_PATH=/build/tmp.RuFeNVpwpH/build/install_hdr/ ARCH=riscv CROSS_COMPILE=riscv64-linux- LLVM=1 'CC=ccache clang' 'HOSTCC=ccache clang' headers_install
tar --sort=name --owner=tuxmake:1000 --group=tuxmake:1000 --mtime=@1776225276 --clamp-mtime -caf /build/tmp.RuFeNVpwpH/build/headers.tar -C /build/tmp.RuFeNVpwpH/build/install_hdr .
warnings/errors:
/build/tmpax261cl6/drivers/perf/riscv_pmu_sbi.c:65:33: error: use of undeclared identifier 'MAX_INTERRUPTS'

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 723.15 seconds
Result: ERROR
Output:

Redirect to /build/tmp.pRdLwKO4j0 and /build/tmp.v4npVeH6HG
Tree base:
506e7f67b3724 ("Adding CI files")
Building the whole tree with the patch
error:
Warning: /build/tmpax261cl6/drivers/pmdomain/mediatek/mtk-mfg-pmdomain.c:244 struct __packed mtk_mfg_opp_entry { __le32 freq_khz; __le32 voltage_core; __le32 voltage_sram; __le32 posdiv; __le32 voltage_margin; __le32 power_mw; }; error: Cannot parse struct or union!
/build/tmpax261cl6/drivers/perf/riscv_pmu_sbi.c:65:33: error: use of undeclared identifier 'MAX_INTERRUPTS'



real	11m56.826s
user	464m24.812s
sys	83m3.405s

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 987.15 seconds
Result: ERROR
Output:

Redirect to /build/tmp.5UdLYTcC5S and /build/tmp.9F3p5mpIwD
Tree base:
506e7f67b3724 ("Adding CI files")
Building the whole tree with the patch
error:
Warning: /build/tmpax261cl6/drivers/pmdomain/mediatek/mtk-mfg-pmdomain.c:244 struct __packed mtk_mfg_opp_entry { __le32 freq_khz; __le32 voltage_core; __le32 voltage_sram; __le32 posdiv; __le32 voltage_margin; __le32 power_mw; }; error: Cannot parse struct or union!
/build/tmpax261cl6/drivers/perf/riscv_pmu_sbi.c:65:40: error: 'MAX_INTERRUPTS' undeclared (first use in this function); did you mean 'PTRACE_INTERRUPT'?
/build/tmpax261cl6/drivers/perf/riscv_pmu_sbi.c:66:1: error: control reaches end of non-void function [-Werror=return-type]



real	16m20.499s
user	644m6.426s
sys	101m36.732s

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 24.98 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 26.42 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 0.75 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 82.98 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.22 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
kdoc
Desc: Detects for kdoc errors
Duration: 0.84 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
module-param
Desc: Detect module_param changes
Duration: 0.24 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.22 seconds
Result: PASS

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linux-riscv-bot commented Apr 15, 2026

Patch 1: "drivers/perf: riscv: do not restart throttled events after overflow"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.29 seconds
Result: PASS

@linux-riscv-bot linux-riscv-bot deleted the pw1081352 branch April 23, 2026 01:56
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