From: Dave Hansen <dave.hansen@intel.com>
To: "Peter Zijlstra" <peterz@infradead.org>, "Jürgen Groß" <jgross@suse.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
llvm@lists.linux.dev, xin@zytor.com,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>
Subject: Re: [PATCH v2 09/12] x86/msr: Use the alternatives mechanism for WRMSR
Date: Fri, 3 Oct 2025 07:23:29 -0700 [thread overview]
Message-ID: <4c4cce9f-3219-48f0-8606-6573339b8794@intel.com> (raw)
In-Reply-To: <20251001072340.GM3245006@noisy.programming.kicks-ass.net>
On 10/1/25 00:23, Peter Zijlstra wrote:
> On Wed, Oct 01, 2025 at 08:43:39AM +0200, Peter Zijlstra wrote:
>> Let me see how terrible it all ends up when using as macros
> Argh, as macros are differently painful. I hate computers :/
ALTERNATIVES are fun and all, but is there a good reason we're pulling
out our hair to use them here?
Normal WRMSR is slooooooooooow. The ones that aren't slow don't need
WRMSRNS in the first place.
Would an out-of-line wrmsr() with an if() in it be so bad? Or a
static_call()? Having WRMSR be inlined in a laudable goal, but I'm
really asking if it's worth it.
next prev parent reply other threads:[~2025-10-03 14:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-30 7:03 [PATCH v2 00/12] x86/msr: Inline rdmsr/wrmsr instructions Juergen Gross
2025-09-30 7:03 ` [PATCH v2 09/12] x86/msr: Use the alternatives mechanism for WRMSR Juergen Gross
2025-09-30 8:31 ` Peter Zijlstra
2025-09-30 8:46 ` Jürgen Groß
2025-09-30 8:50 ` Peter Zijlstra
2025-09-30 12:51 ` Peter Zijlstra
2025-09-30 15:42 ` Jürgen Groß
2025-10-01 6:43 ` Peter Zijlstra
2025-10-01 7:23 ` Peter Zijlstra
2025-10-03 14:23 ` Dave Hansen [this message]
2025-10-03 16:53 ` H. Peter Anvin
2025-10-01 8:49 ` Juergen Gross
2025-10-01 10:50 ` Peter Zijlstra
2025-10-01 11:16 ` Jürgen Groß
2025-09-30 16:00 ` Sean Christopherson
2025-10-01 9:13 ` Jürgen Groß
2025-09-30 19:19 ` [PATCH v2 00/12] x86/msr: Inline rdmsr/wrmsr instructions H. Peter Anvin
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