On Tue, Jan 09, 2018 at 03:02:27PM -0800, Paul Rogers wrote:
> > On Mon, Jan 08, 2018 at 04:14:50PM -0800, Paul Rogers wrote:
> > > I've just patched one of my older Core2 "Conroe", LFS-7.7, up to 4.4.110.
> > > It's an i686 system. <snip>
> > >
> > > Any ideas? TIA.
> > >
> >
> > Looking at my lkml mailbox, patch 02 of 37 for this version added
>
> I haven't been able to GET to LKML for 3 days now. It keeps timing-out.
>
> > Sorry. I'm afraid 32-bit x86 gets much less love these days.
>
> Please, if anyone runs across the 32-bit patch, let me know. There certainly
> are many 32-bit system still in service!
>
> Yes, I can run x86-64 on my Conroes, but it's noticably slower, especially
> for such things as starting X.
>
> >
> > Meassuring LFS builds looks a bit different to me (column 2+3 are build
> > times in seconds and may not be 100% accurate but the trend is clear):
> >
> > Package 4.14.10 .12 Ratio
> > --------------------------------------------
> > 034-binutils-pass1 97 113 1,16
> > 035-gcc-pass1 261 296 1,13
> > 036-linux-headers 6 17 2,83
> > 037-glibc 149 178 1,19
>
> AIUI chips, such as my elderly i7-940, are actually 4 cores that pretend to
> have 8 using the hyperthreading introduced with the Pentium-D. The
> hyperthreaded core is scheduled on an "as resources are available" basis--the
> "real" core has priority. Performance figures I saw back in the day showed a
> hyperthreaded system provided at most 140% of the equivalent single
> core--certainly worth having, but NOT 200%.
>
I have no idea about the changes with each generation, but for
recent models, provided hyperthreading is enabled, linux sees 8
cores in this situation - depending on the kernel config, it might
slightly change how things are scheduled, but overall it rotates
jobs between all cores.
The difference with hyperthreading is that things like
floating-point get shared between siblings.
If I watch 'top' (recent version) I can see an activity line for
each core. And the activity moves around.
> "Wikipedia: According to Intel, the first hyper-threading implementation used
> only 5% more die area than the comparable non-hyperthreaded processor, but
> the performance was 15–30% better. Intel claims up to a 30% performance
> improvement compared with an otherwise identical, non-simultaneous
> multithreading Pentium 4."
>
> So exactly what preceeded the build would change the way tasks got assigned
> to the next available "core", hence what ran on real cores vs hyperthreaded
> "cores" and different timings.
>
ĸen
--
Truth, in front of her huge walk-in wardrobe, selected black leather
boots with stiletto heels for such a barefaced truth.
- Unseen Academicals
--
http://lists.linuxfromscratch.org/listinfo/lfs-support
FAQ: http://www.linuxfromscratch.org/blfs/faq.html
Unsubscribe: See the above information page
Do not top post on this list.
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
http://en.wikipedia.org/wiki/Posting_style
