Re: [Valgrind-users] start_rstsc_calibration causes illegal instruction crash

[Jeremy F. <je...@go...>]

On Fri, 2003-11-21 at 08:59, Daniel Goertzen wrote:
> I am trying to run valgrind on a Cx486DX2 which has no CPUID or RDTSC
> instruction.
> 
> I've managed to get past the CPUID in vg_startup.S with a hack suggested by
> Jeremy, but now I'm trying to figure out the best way around RDSTC.  The
> instuction is called by start_rdtsc_calibration() in vg_main.c.
> 
> Suggestions?  I'm going to keep beating on it for now, but if someone can
> point me down the right path, great!

First question: are you using 2.0 or HEAD?  2.0 is a bit more dependent
on the TSC for timing everything, whereas I think HEAD only needs it to
pthread_cond_timedwait.

Probably the best thing to do is go and find all instances of rdtsc (ie,
calls to do_rdtsc_insn), and replace them with calls to gettimeofday. 
This is something we probably need to do anyway, since many machines
have TSCs which change rate anyway, which makes it useless for us.

	J