On 2/20/2024 8:31 AM, Andrew Davis wrote:
On 2/16/24 2:23 PM, Denys Dmytriyenko wrote:
Unfortunately, NAK.
This is considered an antisocial behavior for a BSP in the Yocto Project
world. And the performance benefit is questionable with 1%-2%, if at all.
This stated when a potential customer noticed building and running some
benchmarks (linpack for instance) on our SDK were being out-performed by
some other vendors. Even though on paper our platforms should have been
the better performing ones.
After investigating it turns out these other vendors have these tune
options in their BSP layers, causing the performance discrepancy.
So the performance here, even of a couple percent, is very important.
The proper place for any extra optimization tunes is in a distro
config. Maybe
even by end customer's final product, not a reference distro.
Consider a distro that supports multiple HW platforms and uses
multiple BSPs
besides meta-ti - YoE, AGL, etc. You do want a common denominator
tunes in
order to get the most binary re-use across the platforms.
If one wants binary re-use they can override the tune. Otherwise maybe
they should be using Debian or some other binary distro. The main selling
point for Yocto IMHO is customizing like this. The best part of rebuilding
everything from scratch every time for every machine is we can have these
machine specific tunings.
For example, AGL goes to some extreme lengths to override such custom
tunes
set by misbehaving BSPs and it's quite ugly.
Then we should work to make it easier to override for those folks, not
simply
leave this performance on the table.
And moreover, we've gone through this motion in the past many years
ago when
we had our ARMv7 platforms set to their corresponding cortex-a8/a9/a15
tunes
by default, but eventually ended up setting a common ARMv7 tune:
DEFAULTTUNE ?= "armv7athf-neon"
So, you should either leave the current arch-arm64.inc inclusion as
is, or if
you insist on including tune-cortexa72-cortexa53.inc, set the default
tune
back to plain aarch64:
DEFAULTTUNE ?= "aarch64"
I see our friends over in meta-xilinx are doing machine specific
DEFAULTTUNEs.
I was thinking of matching that to keep our BSP performance competitive.
But
as a compromise and to avoid "antisocial behavior" as you say, I think I
can
live with DEFAULTTUNE ?= "aarch64".
Will resend with that.
So, if we include the more targeted tuning file, but set DEFAULTUNE to
the generic, then how do our builds use the more targeted tuning? Is
that something we have to set in the local.conf as part of our builds?
Or is this some sort of magic that occurs that gets the correct thing?
Andrew
On Thu, Feb 15, 2024 at 03:26:13PM -0600, Andrew Davis via
lists.yoctoproject.org wrote:
All current K3 devices use either A53 or A72. Use the compile tune
configuration specific for these to allow the compiler to make
better optimizations.
Signed-off-by: Andrew Davis <[email protected]>
---
meta-ti-bsp/conf/machine/include/k3.inc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/meta-ti-bsp/conf/machine/include/k3.inc
b/meta-ti-bsp/conf/machine/include/k3.inc
index 2415f0ba..7c3579af 100644
--- a/meta-ti-bsp/conf/machine/include/k3.inc
+++ b/meta-ti-bsp/conf/machine/include/k3.inc
@@ -3,7 +3,7 @@
require conf/machine/include/ti-soc.inc
SOC_FAMILY:append = ":k3"
-require conf/machine/include/arm/arch-arm64.inc
+require conf/machine/include/arm/armv8a/tune-cortexa72-cortexa53.inc
BBMULTICONFIG += "k3r5"
--
2.39.2
--
Ryan Eatmon [email protected]
-----------------------------------------
Texas Instruments, Inc. - LCPD - MGTS
-=-=-=-=-=-=-=-=-=-=-=-
Links: You receive all messages sent to this group.
View/Reply Online (#17489):
https://lists.yoctoproject.org/g/meta-ti/message/17489
Mute This Topic: https://lists.yoctoproject.org/mt/104381861/21656
Group Owner: [email protected]
Unsubscribe: https://lists.yoctoproject.org/g/meta-ti/unsub
[[email protected]]
-=-=-=-=-=-=-=-=-=-=-=-
