On 06/10/2013 03:33 PM, David Ahern wrote:
On 6/10/13 4:28 PM, Rick Jones wrote:
I think I could get what I want from that - assuming I could get that to
a kernel I can use in my test env, but am guessing it is rather more
than I"m looking for at the moment. I'm wondering if there might be a
simpler way to go - just get the idle loop to keep looping rather than
halt (?) the thread, so there would still be cycle events in the PMU?
(And perhaps set the system to a static, high-performance mode to avoid
frequency changes and maybe even disable HT?)
Or, after having found
https://www.kernel.org/doc/Documentation/kernel-parameters.txt, perhaps
idle=poll?
Yes, that should turn the server into a power-sucking space heater and
keep the cycles counter firing.
Excellent - I can live with the server being a power-sucking space
heater for the duration of my profiling. Heck, many of the servers I
used to work on were always power-sucking space heaters :)
happy benchmarking,
rick jones
Interestingly enough, on the old Centrino-based laptop where I've tried
it (on AC power), read_hpet has gone away completely. I'd noticed that
was visible in several examples in the tutorial on the wiki, but it
wasn't explained.
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