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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-07-03 07:27:52 +0000 |
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| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-07-03 07:27:52 +0000 |
| commit | d0c85e36e4de67af628d54e9ab577cc3fad7796a (patch) | |
| tree | f8f784b0f04343b90516a338d6df81df3a85dfa2 /results/classifier/gemma3:12b/performance/498417 | |
| parent | 7f4364274750eb8cb39a3e7493132fca1c01232e (diff) | |
| download | emulator-bug-study-d0c85e36e4de67af628d54e9ab577cc3fad7796a.tar.gz emulator-bug-study-d0c85e36e4de67af628d54e9ab577cc3fad7796a.zip | |
add deepseek and gemma results
Diffstat (limited to 'results/classifier/gemma3:12b/performance/498417')
| -rw-r--r-- | results/classifier/gemma3:12b/performance/498417 | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/results/classifier/gemma3:12b/performance/498417 b/results/classifier/gemma3:12b/performance/498417 new file mode 100644 index 00000000..586c5db6 --- /dev/null +++ b/results/classifier/gemma3:12b/performance/498417 @@ -0,0 +1,15 @@ + +cache=writeback on disk image doesn't do write-back + +I noticed that qemu seems to have poor disk performance. Here's a test that has miserable performance but which should be really fast: + +- Configure qemu to use the disk image with cache=writeback +- Configure a 2GiB Linux VM on an 8GiB Linux host +- In the VM, write a 4GiB file (dd if=/dev/zero of=/tmp/x bs=4K count=1M) +- In the VM, read it back (dd if=/tmp/x of=/dev/null bs=4K count=1M) + +With writeback, the whole file should end up in the host pagecache. So when I read it back, there should be no I/O to the real disk, and it should be really fast. Instead, I see disk activity through the duration of the test, and the performance is roughly the native hard disk throughput (somewhat slower). + +I'm using version 0.11.1, and this is my command line: + +qemu-system-x86_64 -drive cache=writeback,index=0,media=disk,file=ubuntu.img -k en-us -m 2048 -smp 2 -vnc :3100 -usbdevice tablet -enable-kvm & \ No newline at end of file |