My original problem seems to stem from something that changed in the way that device emulation and instruction execution interact (I'm guessing). To reproduce the issue, I started a linux image with
qemu-system-i386 -rtc clock=vm -monitor none -icount 1,sleep=off jack.img After booting, I run ping localhost The first round trip time reports look reasonable, being in the millisecond to sub-millisecond range. These occur while the emulator is running slower than real time. After a bit, the emulator speeds up (skipping over idle periods during I/O?) and the round trip times jump to hundreds of milliseconds, which I had not expected. If you want to try this experiment yourself, you can get the disk image that I used from here: http://www.ornl.gov/~1qn/qemu-images/jack.img Jim
