Alexander Kolbasov wrote: > I doscussed this with Eric, just wanted to have some online record. > > Li> DTRACE_PROBE2(cpu_change_speed, processorid_t, cpudsp->cpu_id, > Li> uint_t, new_spd->speed); > Li> DTRACE_PROBE2(cpu_change_speed, processorid_t, cpudsp->cpu_id, > Li> uint_t, new_spd->speed); > > In generl it is not a good idea to dereference pointers in DTRACE SDT > probes since this will increase disabled probe effect. It is better to > provide raw pointers (preferably available on the stack already) and > then have translators defined that will defer pointer dereference to > the time when the probe is enabled. > Aubrey was keen enough to point out that the "old speed" pointer (which I added) could be NULL, if the CPU has never undergone a CPU speed change. I was wondering if it would be possible to have the current speed initialized (perhaps at attach / initialization time)? That would save having to worry about having an uninitialized current speed throughout much of the code, including the DTrace probe / translator implementation.
-Eric
