Re: [RFC PATCH 0/4] utrace: new modular infrastructure for user debug/tracing

[Daniel Jacobowitz <dan@debian.org>]

On Fri, Jun 16, 2006 at 10:42:00AM -0400, Frank Ch. Eigler wrote:
> Indeed, I like what I see (at least those parts I understand) in
> roland's utrace code.  One missed opportunity bit appears to be any
> new support for something like per-thread breakpoints.
> 
> If I correctly understand how gdb etc. work, a hit breakpoint involves
> stoppage of all other threads of a process, then the breakpoint
> instruction is replaced by the original one, then the thread is
> single-stepped, then the breakpoint is put back, then finally all
> threads are resumed.  Could utrace API provide short-lived per-thread
> page copies to execute the single-stepped original instruction out of,
> and avoid stopping & resuming all other threads?

FYI: I talked with Roland about this a while ago, and got the
impression that he was interested in implementing it, but wanted to get
utrace going first.  It doesn't really relate to utrace; but it would
need a new interface however it was implemented.

GDB really does crave this feature.

-- 
Daniel Jacobowitz
CodeSourcery