Re: TSC vs. HPET timecounter priority

[Dennis Ferguson <dennis.c.ferguson%gmail.com@localhost>]

On 13 Aug, 2012, at 07:34 , YAMAMOTO Takashi wrote:
>> What about the following patch?
>> tc_quality for hpet is set to 2000 so it would have a higher priority.
>> Using 1500 leave some room for other implementations to have a higher
>> priority then tsc.
> 
> please take a look at tsc_tc_init.

Yes, it would be better to try to fix that to find more TSC-broken
cases, including the one's we're talking about, if possible.  If the
TSC works on your system it is a really good idea to use it.  It is more
precise, it is much cheaper to sample (the HPET is off-chip) and it can
potentially provide system call free time to applications.  Making the
HPET the default in all cases, including those where the TSC works well,
throws those advantages away for most people.

Dennis Ferguson