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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-07-08 13:28:15 +0200 |
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| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-07-08 13:28:28 +0200 |
| commit | 5aa276efcbd67f4300ca1a7f809c6e00aadb03da (patch) | |
| tree | 9b8f0e074014cda8d42f5a97a95bc25082d8b764 /results/classifier/zero-shot-user-mode/runtime/1857 | |
| parent | 1a3c4faf4e0a25ed0b86e8739d5319a634cb9112 (diff) | |
| download | qemu-analysis-5aa276efcbd67f4300ca1a7f809c6e00aadb03da.tar.gz qemu-analysis-5aa276efcbd67f4300ca1a7f809c6e00aadb03da.zip | |
restructure results
Diffstat (limited to 'results/classifier/zero-shot-user-mode/runtime/1857')
| -rw-r--r-- | results/classifier/zero-shot-user-mode/runtime/1857 | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/results/classifier/zero-shot-user-mode/runtime/1857 b/results/classifier/zero-shot-user-mode/runtime/1857 new file mode 100644 index 000000000..94c75b18a --- /dev/null +++ b/results/classifier/zero-shot-user-mode/runtime/1857 @@ -0,0 +1,58 @@ +runtime: 0.445 +instruction: 0.400 +syscall: 0.155 + + + +Major qemu-aarch64 performance slowdown since commit 59b6b42cd3 +Description of problem: +I have observed a major performance slowdown between qemu 8.0.0 and 8.1.0: + + +qemu 8.0.0: 0.8s + +qemu 8.1.0: 6.8s + + +After bisecting the commits between 8.0.0 and 8.1.0, the offending commit is 59b6b42cd3: + + +commit 59b6b42cd3446862567637f3a7ab31d69c9bef51 +Author: Richard Henderson <richard.henderson@linaro.org> +Date: Tue Jun 6 10:19:39 2023 +0100 + + target/arm: Enable FEAT_LSE2 for -cpu max + + Reviewed-by: Peter Maydell <peter.maydell@linaro.org> + Signed-off-by: Richard Henderson <richard.henderson@linaro.org> + Message-id: 20230530191438.411344-21-richard.henderson@linaro.org + Signed-off-by: Peter Maydell <peter.maydell@linaro.org> + + +Reverting the commit in latest master fixes the problem: + +qemu 8.0.0: 0.8s + +qemu 8.1.0: 6.8s + +qemu master + revert 59b6b42cd3: 0.8s + +Alternatively, specify `-cpu cortex-a35` to disable LSE2: + +`time ./qemu-aarch64 -cpu cortex-a35`: 0.8s + +`time ./qemu-aarch64`: 6.77s + +The slowdown is also observed when running qemu-aarch64 on aarch64 machine: + +`time ./qemu-aarch64 /usr/bin/node -e 1`: 2.91s + +`time ./qemu-aarch64 -cpu cortex-a35 /usr/bin/node -e 1`: 1.77s + +The slowdown on x86_64 machine is small: 362ms -> 378ms. +Steps to reproduce: +1. Run `time ./qemu-aarch64 node-aarch64 -e 1` (node-aarch64 is NodeJS v16 built for AArch64) +2. Using qemu master, the output says `0.8s` +3. Using qemu master with commit 59b6b42cd3 reverted, the output says `6.77s` +Additional information: + |