On 2021-12-11 02:38, David Chisnall wrote:
While I agree on most of your points, the value of Phoronix is that it tests
the
default install.
As an end user, I don’t care that a particular program is twice as fast on a
particular Linux distro as it is on FreeBSD because of kernel features,
compiler
options, or dependency choices.
I would love to see the base system include the ThinLTO (LLVM IR) .a files
so that
I can do inlining from libc into my program. I would love for ports to
default to
ThinLTO unless they break with it. Apple flipped that switch a few years
ago, so
a lot of things that broke with ThinLTO are now fixed.
The FreeBSD memcpy / memset implementations look like they’re slower than
the
latest ones, which can give a 5-10% perf boost on some workloads. LLVM just
landed the automemcpy framework, which is designed by some Google folks to
synthesises efficient memcpy implementations tailored to different
workloads.
FreeBSD often wins versus glibc-based distros because jemalloc is faster
than
dlmalloc (the default malloc implementations in FreeBSD libc and glibc,
respectively). I’ve been using snmalloc in my libc for a while and it
generally
gives me a few percent more perf. Unfortunately, FreeBSD decided to expose
all of
the jemalloc non-standard functions from libc, which means I can’t
contribute it
to upstream without implementing all of those on top of snmalloc or it would
be an
ABI break.
It would be great if someone could pick up the Phronix benchmark suite and
do some
profiling: where is FreeBSD spending more time than Linux? Are there
Linux-specific code paths that hit slow paths on FreeBSD and fast paths on
Linux
that could have FreeBSD-specific fast paths added (e.g. futex vs _umtx_op)?
I think everyones (here) making good points on the comparisons made on/at
Phronix.
But given that the FreeBSD "default" install adds a fair amount of overhead
to
elicit good feedback for bugs/failures. It makes it a poor candidate (kernel)
for
comparing performance. Hell, dmesg(8) even throws a warning saying that
performance
will be encumbered.
If they knew the BSD basics. They might be able to provide a more meaningful
comparison.
I'm going to add Creating a BSD vs Linux comparison to the Foundation
Sponsored Request/poll
recently posted on some of the mailing lists. It'd be great for
promotion/advertising/evangelism. :-)
-- Chris
David
On 11 Dec 2021, at 10:17, dmilith . <dmil...@gmail.com> wrote:
1. Where are compiler options for BSDs?
2. Why they compare -O2 to -O3 code in some benchmarks? Why they enable
fast math in some, and disable it for others?
3. Why they don't mention powerd setup for FreeBSD? By default it may use
slowest CPU mode. Did they even load cpufreq kernel module?
4. Did they even care about default FreeBSD mitigations (via sysctl)
enabled, or it's only valid for Linuxes? ;)
5. What happened to security and environment details of BSDs?
It's kinda known that guys from Phroenix lack basic knowledge of how to do
proper performance testing and lack basic knowledge about BSD systems.
Nothing new. Would take these results with a grain of salt.
On Sat, 11 Dec 2021 at 10:53, beepc.ch <xpe...@beepc.ch> wrote:
I am surprised to see that the BSD cluster today has much worse
performance
than Linux.
What do you think of this?
"Default" FreeBSD install setting are quite conservative.
The Linux common distros are high tuned, those benchmark is in my
opinion comparison of apples and oranges.
Comparing "default" FreeBSD install with "default" Slackware install
would be more interesting, because Slackware builds are at most vanilla.
--
Daniel Dettlaff
Versatile Knowledge Systems
verknowsys.com
