Re: [PATCH RFC V2 3/3] scsi_mq: enable runtime PM

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, 19 Jul 2018, Johannes Thumshirn wrote:

> On Wed, Jul 18, 2018 at 11:01:52AM -0400, Alan Stern wrote:
> > On Wed, 18 Jul 2018, Johannes Thumshirn wrote:
> > 
> > > On Wed, Jul 18, 2018 at 10:12:37AM -0400, Alan Stern wrote:
> > > > As one extra reminder...  People who care about extreme performance can 
> > > > perfectly well disable CONFIG_PM in their kernels.  That should remove 
> > > > any overhead due to runtime PM.
> > > 
> > > Yes but how likely is this for people who are running their data
> > > center with a distribution kernel.
> > 
> > Strictly speaking, that's a nonsense question.  People who run 
> > distribution kernels are 100% unlikely to change the kernel 
> > configuration, by definition.
> > 
> > That's not the point.  If people really care about getting the utmost 
> > performance, to the extent that they resent the minimal overhead 
> > required for runtime PM, then they should not be running distribution 
> > kernels in the first place.
> 
> Can we agree to disagree here?
> 
> Some of the people I know in HPC, HFT, etc... run stock SLE/RHEL and
> they do file bugs for every single 3-5% performance regression. This
> is not something I made up, this is the kind of things I have to deal
> with on my day job.

The performance affect of runtime PM ought to be less than 1%.  If it
is larger, we'll figure out a different approach.

Alan Stern




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]

  Powered by Linux