Performance Benchmark for PTI (aka Meltdown mitigation)

[Arshan Khanifar]

I did some benchmarking for the two revisions:
results are here:
https://github.com/ArshanKhanifar/pti-benchmark/tree/master/stable-11-pre-after/results
first file is before pti patch and second file is after pti patch.

On Fri, Mar 9, 2018 at 10:16 AM, Slawa Olhovchenkov <slw at zxy.spb.ru> wrote:

> On Fri, Mar 09, 2018 at 09:58:55AM -0500, Ed Maste wrote:
>
> > On 9 March 2018 at 07:01, Slawa Olhovchenkov <slw at zxy.spb.ru> wrote:
> > > On Thu, Mar 08, 2018 at 05:04:11PM -0500, Arshan Khanifar wrote:
> > >
> > >> Executive Summary:
> > >> - The PTI feature increases the system call times by more than 100%.
> > >> - As a macrobenchmark, buildworld was used. Wall clock and user time
> > >> showed no statistically-significant changes, while system time
> > >> increased by less than 5%.
> > >>
> > >> This email contains the results for benchmarking the performance of
> the
> > >> PTI patch on FreeBSD 12-current. As a microbenchmark, timing of
> > >> getppid(2) system call was used, and as a macrobenchmark, a number of
> > >> buildworld tasks were timed.
> > >>
> > >
> > > Can you also run pre-patched kernel?
> >
> > It's not easy to do an apples-to-apples comparison as there were a few
> > followup changes to the PTI work, interspersed with unrelated changes.
> > That said, I think Arshan has some benchmarks obtained during the
> > development of the PTI changes that may be illustrative.
> >
> > The best approach is probably to compare stable/11 at r329450 (last
> > stable/11 revision before the merge) with r329462 with PTI and IBRS
> > disabled.
>
> Stable/11 more interesting to me, nice to see.
>
>