On 8/5/2021 10:29 PM, Dave Hansen wrote:
On 8/5/21 7:23 AM, Peter Zijlstra wrote:
This is assuming any of this is actually performance critical, based off
of this using static_call() to begin with.
This code is not performance critical.
I think I sent folks off on a wild goose chase when I asked that we make
an effort to optimize code that does:
if (some_hyperv_check())
foo();
if (some_amd_feature_check())
bar();
with checks that will actually compile away when Hyper-V or
some_amd_feature() is disabled. That's less about performance and just
about good hygiene. I *wanted* to see
cpu_feature_enabled(X86_FEATURE...) checks.
Someone suggested using static calls, and off we went...
Could we please just use cpu_feature_enabled()?
Yes, cpu_feature_enabled() works. The target is just to run platform
code after platform check. I will update this in the next version.