Re: perf-stat changes after "Use hrtimers for event multiplexing"

2014-01-07 Thread Stephane Eranian
On Tue, Jan 7, 2014 at 2:20 PM, Fengguang Wu wrote: > Hi Stephane, > > On Tue, Jan 07, 2014 at 10:52:50AM +0100, Stephane Eranian wrote: >> Hi, >> >> With the hrtitmer patch, you will get more regular multiplexing when >> you have idle cores during your benchmark. >> Without the patch,

Re: perf-stat changes after "Use hrtimers for event multiplexing"

2014-01-07 Thread Fengguang Wu
Hi Stephane, On Tue, Jan 07, 2014 at 10:52:50AM +0100, Stephane Eranian wrote: > Hi, > > With the hrtitmer patch, you will get more regular multiplexing when > you have idle cores during your benchmark. > Without the patch, multiplexing was piggybacked on timer tick. The > timer tick does not

Re: perf-stat changes after "Use hrtimers for event multiplexing"

2014-01-07 Thread Stephane Eranian
Hi, With the hrtitmer patch, you will get more regular multiplexing when you have idle cores during your benchmark. Without the patch, multiplexing was piggybacked on timer tick. The timer tick does not occur when a core is idle when using a tickless kernel. Thus, the quality of the results with

Re: perf-stat changes after Use hrtimers for event multiplexing

2014-01-07 Thread Stephane Eranian
Hi, With the hrtitmer patch, you will get more regular multiplexing when you have idle cores during your benchmark. Without the patch, multiplexing was piggybacked on timer tick. The timer tick does not occur when a core is idle when using a tickless kernel. Thus, the quality of the results with

Re: perf-stat changes after Use hrtimers for event multiplexing

2014-01-07 Thread Fengguang Wu
Hi Stephane, On Tue, Jan 07, 2014 at 10:52:50AM +0100, Stephane Eranian wrote: Hi, With the hrtitmer patch, you will get more regular multiplexing when you have idle cores during your benchmark. Without the patch, multiplexing was piggybacked on timer tick. The timer tick does not occur

Re: perf-stat changes after Use hrtimers for event multiplexing

2014-01-07 Thread Stephane Eranian
On Tue, Jan 7, 2014 at 2:20 PM, Fengguang Wu fengguang...@intel.com wrote: Hi Stephane, On Tue, Jan 07, 2014 at 10:52:50AM +0100, Stephane Eranian wrote: Hi, With the hrtitmer patch, you will get more regular multiplexing when you have idle cores during your benchmark. Without the patch,

Re: perf-stat changes after "Use hrtimers for event multiplexing"

2014-01-04 Thread Fengguang Wu
On Sat, Jan 04, 2014 at 08:02:28PM +0100, Peter Zijlstra wrote: > On Thu, Jan 02, 2014 at 02:12:42PM +0800, fengguang...@intel.com wrote: > > Greetings, > > > > We noticed many perf-stat changes between commit 9e6302056f ("perf: Use > > hrtimers for event multiplexing") and its parent commit

Re: perf-stat changes after "Use hrtimers for event multiplexing"

2014-01-04 Thread Peter Zijlstra
On Thu, Jan 02, 2014 at 02:12:42PM +0800, fengguang...@intel.com wrote: > Greetings, > > We noticed many perf-stat changes between commit 9e6302056f ("perf: Use > hrtimers for event multiplexing") and its parent commit ab573844e. > Are these expected changes? > > ab573844e3058ee

Re: perf-stat changes after Use hrtimers for event multiplexing

2014-01-04 Thread Peter Zijlstra
On Thu, Jan 02, 2014 at 02:12:42PM +0800, fengguang...@intel.com wrote: Greetings, We noticed many perf-stat changes between commit 9e6302056f (perf: Use hrtimers for event multiplexing) and its parent commit ab573844e. Are these expected changes? ab573844e3058ee

Re: perf-stat changes after Use hrtimers for event multiplexing

2014-01-04 Thread Fengguang Wu
On Sat, Jan 04, 2014 at 08:02:28PM +0100, Peter Zijlstra wrote: On Thu, Jan 02, 2014 at 02:12:42PM +0800, fengguang...@intel.com wrote: Greetings, We noticed many perf-stat changes between commit 9e6302056f (perf: Use hrtimers for event multiplexing) and its parent commit ab573844e.