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Diffstat (limited to 'results/scraper/launchpad-without-comments/1253563')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1253563 | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1253563 b/results/scraper/launchpad-without-comments/1253563 new file mode 100644 index 00000000..42dca079 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1253563 @@ -0,0 +1,34 @@ +bad performance with rng-egd backend + + +1. create listen socket +# cat /dev/random | nc -l localhost 1024 + +2. start vm with rng-egd backend + +./x86_64-softmmu/qemu-system-x86_64 --enable-kvm -mon chardev=qmp,mode=control,pretty=on -chardev socket,id=qmp,host=localhost,port=1234,server,nowait -m 2000 -device virtio-net-pci,netdev=h1,id=vnet0 -netdev tap,id=h1 -vnc :0 -drive file=/images/RHEL-64-virtio.qcow2 \ +-chardev socket,host=localhost,port=1024,id=chr0 \ +-object rng-egd,chardev=chr0,id=rng0 \ +-device virtio-rng-pci,rng=rng0,max-bytes=1024000,period=1000 + +(guest) # dd if=/dev/hwrng of=/dev/null + +note: cancelling dd process by Ctrl+c, it will return the read speed. + +Problem: the speed is around 1k/s + +=================== + +If I use rng-random backend (filename=/dev/random), the speed is about 350k/s). + +It seems that when the request entry is added to the list, we don't read the data from queue list immediately. +The chr_read() is delayed, the virtio_notify() is delayed. the next request will also be delayed. It effects the speed. + +I tried to change rng_egd_chr_can_read() always returns 1, the speed is improved to (about 400k/s) + +Problem: we can't poll the content in time currently + + +Any thoughts? + +Thanks, Amos \ No newline at end of file |