When we make changes to the TCG we sometimes cause regressions that are deep into the execution cycle of the guest. Debugging this often requires comparing large volumes of trace information to figure out where behaviour has diverged. The lockstep plugin utilises a shared socket so two QEMU's running with the plugin will write their current execution position and wait to receive the position of their partner process. When execution diverges the plugins output where they were and the previous few blocks before unloading themselves and letting execution continue. Originally I planned for this to be most useful with -icount but it turns out you can get divergence pretty quickly due to asynchronous qemu_cpu_kick_rr_cpus() events causing one side to eventually run into a short block a few cycles before the other side. For this reason I've added a bit of tracking and I think the divergence reporting could be finessed to report only if we really start to diverge in execution. An example run would be: qemu-system-sparc -monitor none -parallel none -net none \ -M SS-20 -m 256 -kernel day11/zImage.elf \ -plugin ./tests/plugin/liblockstep.so,arg=lockstep-sparc.sock \ -d plugin,nochain with an identical command in another window in the same working directory. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Robert Foley <robert.foley@linaro.org> Tested-by: Robert Foley <robert.foley@linaro.org> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Message-Id: <20200610155509.12850-3-alex.bennee@linaro.org> |
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aarch64 | ||
alpha | ||
arm | ||
cris | ||
hppa | ||
i386 | ||
lm32 | ||
m68k | ||
minilib | ||
mips | ||
multiarch | ||
openrisc | ||
ppc | ||
s390x | ||
sh4 | ||
sparc64 | ||
x86_64 | ||
xtensa | ||
.gitignore | ||
configure.sh | ||
Makefile.prereqs | ||
Makefile.qemu | ||
Makefile.target | ||
README |
This directory contains various interesting guest programs for regression testing. Tests are either multi-arch, meaning they can be built for all guest architectures that support linux-user executable, or they are architecture specific. CRIS ==== The testsuite for CRIS is in tests/tcg/cris. You can run it with "make test-cris". LM32 ==== The testsuite for LM32 is in tests/tcg/lm32. You can run it with "make test-lm32".