On Thu, May 14, 2015 at 05:43:52PM +0100, Peter Maydell wrote: > This patchset adds support for two new commands to our > gdb scripts, which allow dynamically enabling and disabling > tracing of events, like this: > > (gdb) source scripts/qemu-gdb.py > (gdb) qemu trace-enable translate_block > Enabled trace event translate_block > Breakpoint 1 at 0xb634f: file ../trace/generated-tracers.h, line 4734. > (gdb) run > [...] > translate_block: tb:0x7fffc69ce010, pc:0x40000000, tb_code:0x7fffd39ce000 > translate_block: tb:0x7fffc69ce078, pc:0x40010000, tb_code:0x7fffd39ce140 > translate_block: tb:0x7fffc69ce0e0, pc:0x40010034, tb_code:0x7fffd39ce180 > translate_block: tb:0x7fffc69ce148, pc:0x40013700, tb_code:0x7fffd39ce1d0 > translate_block: tb:0x7fffc69ce1b0, pc:0x40013710, tb_code:0x7fffd39ce270 > translate_block: tb:0x7fffc69ce218, pc:0x4001003c, tb_code:0x7fffd39ce310 > [etc] > > This works by setting custom breakpoints on the stub functions > trace_<eventname> that the null tracing backend creates. It > probably doesn't work with an optimised build, but on the other > hand because it's purely implemented within gdb you can use a > tool like 'rr' (http://rr-project.org/) to record a run with no > tracing enabled and then turn the tracing on and off as you desire > during the replay.
Did you try GDB's static probe points support? https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html I think QEMU binaries built with the SystemTap/DTrace backend can be traced by GDB. Stefan
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