i386/135447: [i386] [request] Intel Core i7 and Nehalem-EP new features not supported

[Dmitry Kubov]

The following reply was made to PR i386/135447; it has been noted by GNATS.

From: Dmitry Kubov <dk at garant.ru>
To: Alexander Motin <mav at FreeBSD.org>
Cc: Andriy Gapon <avg at FreeBSD.org>, jh at FreeBSD.org,
        bug-followup <bug-followup at FreeBSD.org>
Subject: Re: i386/135447: [i386] [request] Intel Core i7 and Nehalem-EP new
 features not supported
Date: Thu, 23 Sep 2010 16:48:18 +0400

 > This CPU has only 266MHz TurboBoost speedup. And some part of it
 > (probably half) could be enabled all the time. This benefit still could
 > be overweighted by C-states latencies penalty. It could be interesting
 > to test some other workloads, like compilation with different number of
 > threads.
 >
 
 Actually tested 8.1-RELEASE with both TurboBoost options in BIOS:
 
 TurboBoost OFF
 Ubench Single CPU:   451935 (0.40s)
 Ubench Single CPU:   450927 (0.40s)
 Ubench Single CPU:   450486 (0.40s)
 
 TurboBoost ON
 Ubench Single CPU:   450890 (0.40s)
 Ubench Single CPU:   450890 (0.40s)
 Ubench Single CPU:   449926 (0.40s)
 
 C-states latencies penalty is reasonable idea. But looks like P0-state 
 not activated at all.
 What about too high %% for C3 state during heavy load:
 dev.cpu.0.cx_usage: 0.17% 0.06% 99.75% last 7560us
 
 > Disk performance fix is reasonable. Some recent improvements in
 > 9-CURRENT should improve it even more. What's about ubench - try some
 > different load.
 >
 Can you suggest other CPU only benchmark?
 
 make -j 16 buildworld
 can't load all cores, can't see less than 11% idle