lkml.org 
[lkml]   [2015]   [Feb]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods
>>
>> there's a few others as well that I'm chasing down...
>> .. but the flip side, prior to running ring 3 code, why NOT do fast expedites?
>
> It would be good to have before-and-after measurements of actual
> boot time. Are these numbers available?


To show the boot time, I'm using the timestamp of the "Write protecting" line,
that's pretty much the last thing we print prior to ring 3 execution.

A kernel with default RCU behavior (inside KVM, only virtual devices) looks like this:

[ 0.038724] Write protecting the kernel read-only data: 10240k

a kernel with expedited RCU (using the command line option, so that I don't have
to recompile between measurements and thus am completely oranges-to-oranges)

[ 0.031768] Write protecting the kernel read-only data: 10240k

which, in percentage, is an 18% improvement.



\
 
 \ /
  Last update: 2015-02-21 17:01    [W:0.071 / U:0.188 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site