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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-07-06 16:43:19 +0000 |
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| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-07-06 16:43:19 +0000 |
| commit | 238ec2b7cc1557d6f34c33cc482e4d0cd3e266dd (patch) | |
| tree | cd8a1b75ba7b3543eb7fe6857f408e7be4d9fd0b /results/classifier/gemma3:27b/runtime/1857 | |
| parent | 96049c939b1916d80532630d63c14e04d5244f1d (diff) | |
| download | qemu-analysis-238ec2b7cc1557d6f34c33cc482e4d0cd3e266dd.tar.gz qemu-analysis-238ec2b7cc1557d6f34c33cc482e4d0cd3e266dd.zip | |
add results
Diffstat (limited to 'results/classifier/gemma3:27b/runtime/1857')
| -rw-r--r-- | results/classifier/gemma3:27b/runtime/1857 | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/results/classifier/gemma3:27b/runtime/1857 b/results/classifier/gemma3:27b/runtime/1857 new file mode 100644 index 000000000..64840da4c --- /dev/null +++ b/results/classifier/gemma3:27b/runtime/1857 @@ -0,0 +1,55 @@ + + + +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: + |