Messages in this thread | | | From | "Longepe, Philippe" <> | Subject | RE: Performance drop on Baytrail with 4.5-rc2 | Date | Tue, 2 Feb 2016 10:33:11 +0000 |
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Hi Thomas,
Yes, this new algorithm is intented to improve the performance versus power efficiency.
Can you please provide us the exact instructions to reproduce your test ?
Best Regards,
Philippe,
________________________________________ From: Thomas Voegtle [tv@lio96.de] Sent: Monday, February 01, 2016 9:34 PM To: Longepe, Philippe Cc: linux-kernel@vger.kernel.org; Gasparini, Stephane; Wysocki, Rafael J Subject: Performance drop on Baytrail with 4.5-rc2
Hi,
I have a Celeron J1900 system (Asrock Q1900B-ITX) always running the latest kernel. Since running the 4.5-rc2 kernel I have a performance drop in a ffmpeg benchmark compared to 4.4. Converting a piece of mpeg to mp4 (to /dev/null).
4.1 made the benchmark in 74s, 4.4 in 75s and now the 4.5-rc2 in 80s.
As the benchmark is very stable in results I easily could bisest it down to the commit:
commit e70eed2b64545ab5c9d2f4d43372d79762f1b985 Author: Philippe Longepe <philippe.longepe@intel.com> Date: Fri Dec 4 17:40:32 2015 +0100
cpufreq: intel_pstate: Account for non C0 time
I can revert this commit on top on 4.5-rc2 (4 of 5 hunks) and then the benchmark is down to 76s.
Was this intended to decrease energy consumption?
Thomas
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