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Diffstat (limited to 'results/scraper/launchpad-without-comments/1774677')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1774677 | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1774677 b/results/scraper/launchpad-without-comments/1774677 new file mode 100644 index 00000000..657f465a --- /dev/null +++ b/results/scraper/launchpad-without-comments/1774677 @@ -0,0 +1,20 @@ +-icount increases boot time by >10x + +When I specify the -icount option, some guest operations such as booting a Linux kernel take more than 10 times longer than otherwise. For example, the following will boot Aboriginal Linux to the login prompt about 6 seconds on my system (using TCG, not KVM): + +wget http://landley.net/aboriginal/downloads/old/binaries/1.4.5/system-image-i686.tar.gz +gunzip <system-image-i686.tar.gz | tar xfv - +cd system-image-i686 +sh run-emulator.sh + +If I replace the last line with + +QEMU_EXTRA="-icount shift=auto" sh run-emulator.sh + +booting to the login prompt takes about 1 minute 20 seconds. + +I have tried different values for "shift" other than the "auto" used above, but have not been able to find one that gives reasonable performance. Specifying "sleep=off" also did not help. + +During the slow boots, qemu appears to spend most of its time sleeping, not using the host CPU. + +I see this with multiple versions of qemu, including current git sources (c181ddaa176856b3cd2dfd12bbcf25fa9c884a97), and on multiple host OSes, including Debian 9 on x86_64. \ No newline at end of file |