[RFC PATCH 1/3] conf/machine/include: add x86-64-v3 tunes (AVX, AVX2, BMI1, BMI2, F16C, FMA, LZCNT, MOVBE, XSAVE)

* [RFC PATCH 1/3] conf/machine/include: add x86-64-v3 tunes (AVX, AVX2, BMI1, BMI2, F16C, FMA, LZCNT, MOVBE, XSAVE)
@ 2022-12-26  8:44 Alexander Kanavin
  2022-12-26  8:44 ` [RFC PATCH 2/3] qemux86-64: build for x86-64-v3 (2013 Haswell and later) rather than Core 2 from 2006 Alexander Kanavin
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Alexander Kanavin @ 2022-12-26  8:44 UTC (permalink / raw)
  To: openembedded-core; +Cc: Alexander Kanavin

Qemu 7.2 finally allows us to move beyond building for original Core 2/Core i7 era hardware,
and this patch adds support for the newer generations. But first, a bit of
background:

Recently toolchains gained support for specifying x86-64 'levels' of
instruction set support; v3 corresponds to 2013-era Haswell CPUs
(and later), with AVX, AVX2 and a few other instructions that
were introduced in that generation. I believe this is preferrable
to picking a specific CPU model as the baseline.

Here's Phoronix's feature article that explains the feature and the available levels:

"Both LLVM Clang 12 and GCC 11 are ready to go in offering the new x86-64-v2, x86-64-v3, and x86-64-v4 targets.

These x86_64 micro-architecture feature levels have been about coming up with a few "classes" of Intel/AMD CPU processor support rather than continuing to rely on just the x86_64 baseline or targeting a
specific CPU family for optimizations. These new levels make it easier to raise the base requirements around Linux x86-64 whether it be for a Linux distribution or a particular software application where
the developer/ISV may be wanting to compile with greater instruction set extensions enabled in catering to more recent Intel/AMD CPUs."

https://www.phoronix.com/news/GCC-11-x86-64-Feature-Levels

Here's gcc docs for it:
https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html

And here's the formal specification (click on the pdf link):
https://gitlab.com/x86-psABIs/x86-64-ABI

The actual tune file was created by copying corei7 tunes and doing
search/replace on them. Qemu options were dropped as unnecessary.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
---
 .../machine/include/x86/tune-x86-64-v3.inc    | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 meta/conf/machine/include/x86/tune-x86-64-v3.inc

diff --git a/meta/conf/machine/include/x86/tune-x86-64-v3.inc b/meta/conf/machine/include/x86/tune-x86-64-v3.inc
new file mode 100644
index 0000000000..365e23b49b
--- /dev/null
+++ b/meta/conf/machine/include/x86/tune-x86-64-v3.inc
@@ -0,0 +1,35 @@
+# Settings for the GCC(1) cpu-type "x86-64-v3":
+#
+#     CPUs with AVX, AVX2, BMI1, BMI2, F16C, FMA, LZCNT, MOVBE, XSAVE.
+#     (but not AVX512).
+#     See https://www.phoronix.com/news/GCC-11-x86-64-Feature-Levels for details.
+#
+# This tune is recommended for Intel Haswell/AMD Excavator CPUs (and later).
+#
+DEFAULTTUNE ?= "x86-64-v3-64"
+
+# Include the previous tune to pull in PACKAGE_EXTRA_ARCHS
+require conf/machine/include/x86/tune-corei7.inc
+
+# Extra tune features
+TUNEVALID[x86-64-v3] = "Enable x86-64-v3 specific processor optimizations"
+TUNE_CCARGS .= "${@bb.utils.contains('TUNE_FEATURES', 'x86-64-v3', ' -march=x86-64-v3', '', d)}"
+
+# Extra tune selections
+AVAILTUNES += "x86-64-v3-32"
+TUNE_FEATURES:tune-x86-64-v3-32 = "${TUNE_FEATURES:tune-x86} x86-64-v3"
+BASE_LIB:tune-x86-64-v3-32 = "lib"
+TUNE_PKGARCH:tune-x86-64-v3-32 = "x86-64-v3-32"
+PACKAGE_EXTRA_ARCHS:tune-x86-64-v3-32 = "${PACKAGE_EXTRA_ARCHS:tune-corei7-32} x86-64-v3-32"
+
+AVAILTUNES += "x86-64-v3-64"
+TUNE_FEATURES:tune-x86-64-v3-64 = "${TUNE_FEATURES:tune-x86-64} x86-64-v3"
+BASE_LIB:tune-x86-64-v3-64 = "lib64"
+TUNE_PKGARCH:tune-x86-64-v3-64 = "x86-64-v3-64"
+PACKAGE_EXTRA_ARCHS:tune-x86-64-v3-64 = "${PACKAGE_EXTRA_ARCHS:tune-corei7-64} x86-64-v3-64"
+
+AVAILTUNES += "x86-64-v3-64-x32"
+TUNE_FEATURES:tune-x86-64-v3-64-x32 = "${TUNE_FEATURES:tune-x86-64-x32} x86-64-v3"
+BASE_LIB:tune-x86-64-v3-64-x32 = "libx32"
+TUNE_PKGARCH:tune-x86-64-v3-64-x32 = "x86-64-v3-64-x32"
+PACKAGE_EXTRA_ARCHS:tune-x86-64-v3-64-x32 = "${PACKAGE_EXTRA_ARCHS:tune-corei7-64-x32} x86-64-v3-64-x32"
-- 
2.30.2



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