Re: Call for Foundation-supported Project Ideas

Regarding the suggestions to either improve or replace the ULE
scheduler, I would like to share another observation.

Usually when I need to zero out HDDs using dd, I use a live Linux.
This time I did that on FreeBSD (13).
My observations:
- On the same hardware, the data transfer rate is a small fraction
(about 1/4th) of which is achieved by Linux.
- The first dd process, which erases the first HDD, gets almost all
CPU and I/O time. The second process which does the second HDD is
getting starved. It actually really starts only after the first one
finished.

To me it was *very* surprising to find out that, while erasing two
similar HDDs concurrently takes about one day on Linux, on FreeBSD,
the first HDD was finished after three days, and only after that the
remaining second dd process got the same CPU time, making it proceed
fast instead of creepingly slowly.

So I guess this might be a scheduler issue.
I certainly will do some tests using the old scheduler when I got time.
And, I ask myself:
Could it be a good idea to sponsor porting the Dragonfly scheduler to FreeBSD?

On 12/2/21, Johannes Totz <jo@bruelltuete.com> wrote:
> On 29/11/2021 03:17, Ed Maste wrote:
>> On Sun, 28 Nov 2021 at 19:37, Steve Kargl
>> <sgk@troutmask.apl.washington.edu> wrote:
>>>
>>> It's certainly not the latest and greatest,
>>> CPU: Intel(R) Core(TM)2 Duo CPU     T7250  @ 2.00GHz (1995.04-MHz
>>> K8-class CPU)
>>
>> If you're content to use a compiler from a package you can save a lot
>> of time by building with `CROSS_TOOLCHAIN=llvm13` and
>> `WITHOUT_TOOLCHAIN=yes`. Or, instead of WITHOUT_TOOLCHAIN perhaps
>> `WITHOUT_CLANG=yes`, `WITHOUT_LLD=yes` and `WITHOUT_LLDB=yes`.
>
> (re-send to list, sorry)
> Can we disconnect the compiler optimisation flag for base and clang? I
> don't need the compiler to be build with -O2 but I want the resulting
> base system to have optimisations enabled.
> Right now, looks like both get -O2 and a lot of time is spent on
> optimising the compiler (for no good reason).
>
>