Stefan Weil <s...@weilnetz.de> writes:
> Am 27.01.21 um 20:52 schrieb Alex Bennée: > >> For example - debian-buster (arm64) running ffmpeg: >> >> alex.bennee@8cd150a4b35d:~/lsrc/qemu.git/builds/all.tci$ ./qemu-aarch64 >> /usr/bin/ffmpeg -i theora.mkv theora.webm >> TODO ../../tcg/tci.c:882: tcg_qemu_tb_exec() >> ../../tcg/tci.c:882: tcg fatal error >> qemu: uncaught target signal 11 (Segmentation fault) - core dumped >> Segmentation fault (core dumped) > > > Thanks. All I tried to say is that I prefer to replace those TODO > statements by working code as soon as there was a case which triggers > them. Most of those TODO statements are very easy to implement, so > anyone can add them when he/she detects a missing one. If I get > information about a scenario which triggers a missing TODO, I'll fix > that of course. I just don't want to add that missing code blindly. Your just going to end up playing wack-a-mole: TODO ../../tcg/tci.c:620: tcg_qemu_tb_exec()me=00:00:00.00 bitrate=N/A speed= 0x ../../tcg/tci.c:620: tcg fatal error qemu: uncaught target signal 11 (Segmentation fault) - core dumped Segmentation fault (core dumped) > Using `make check-tcg` helped finding and fixing one of them, future > improved CI checks can find more, and so can examples like the one > above. The error message tci.c:882 is INDEX_op_ld8s_i64 > (https://github.com/qemu/qemu/blob/master/tcg/tci.c#L882). The missing > code is nearly identical to the existing code for INDEX_op_ld8u_i64, but > with *(int8_t *) instead of *(uint8_t *), so maybe you can try that and > confirm whether it fixes the reported problem. Otherwise I'll try to > reproduce it with any mkv file. ffmpeg is a good application for working out the SIMD code because it features quite a lot of optimised code for each architecture. > I recently tried running tesseract with qemu-x86_64 because I had > expected that it might trigger some unimplemented TCG opcodes. qemu-x86-64 is a poor choice as a relatively under maintained front-end doesn't emulate a particularly new CPU or take advantage of the new TCG features. ARM64 is pretty good because the default cpu for linux-user is CPU max which a) enables all ISA features we have and b) exposes them fairly easily to guest detection routines which probe feature registers. > Instead > it showed a general problem for native TCG: qemu-x86_64 allocates too > much memory for tesseract and gets killed by the Linux kernel OOM > handler. Do you have a command line? That sounds like something that should be fixed. > > Regards, > > Stefan -- Alex Bennée
