linux-kernel - Re: [PATCH V2 1/8] perf/x86/intel/P4: Fix smp_num

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Date:   Tue, 16 Aug 2022 17:47:14 +0800
From:   Zhang Rui <rui.zhang@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-hwmon@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, hpa@...or.com,
        corbet@....net, fenghua.yu@...el.com, jdelvare@...e.com,
        linux@...ck-us.net, len.brown@...el.com
Subject: Re: [PATCH V2 1/8] perf/x86/intel/P4: Fix smp_num_siblings usage

On Tue, 2022-08-16 at 10:27 +0200, Peter Zijlstra wrote:
> On Tue, Aug 16, 2022 at 01:16:26PM +0800, Zhang Rui wrote:
> > smp_num_siblings can be larger than 2.
> > 
> > Any value larger than 1 suggests HT is supported.
> 
> Subject and Changelog are still utterly insane.

what about this one, do I need to resend the full series?

thanks,
rui

>From 2e368e6afa83cb73e44ac8c3cf8339207097d9e1 Mon Sep 17 00:00:00 2001
From: Zhang Rui <rui.zhang@...el.com>
Date: Tue, 28 Jun 2022 11:02:12 +0800
Subject: [PATCH V3 1/8] perf/x86/intel/P4: unify logic for detecting HT

Any value larger than 1 suggests HT is supported.

Although smp_num_siblings cannot be larger than 2 on P4 platform, it is
better to keep this logic consistent across the kernel.

Reviewed-by: Len Brown <len.brown@...el.com>
Signed-off-by: Zhang Rui <rui.zhang@...el.com>
---
 arch/x86/include/asm/perf_event_p4.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/perf_event_p4.h
b/arch/x86/include/asm/perf_event_p4.h
index 94de1a05aeba..b14e9a20a7c0 100644
--- a/arch/x86/include/asm/perf_event_p4.h
+++ b/arch/x86/include/asm/perf_event_p4.h
@@ -189,7 +189,7 @@ static inline int p4_ht_active(void)
 static inline int p4_ht_thread(int cpu)
 {
 #ifdef CONFIG_SMP
-	if (smp_num_siblings == 2)
+	if (smp_num_siblings > 1)
 		return cpu !=
cpumask_first(this_cpu_cpumask_var_ptr(cpu_sibling_map));
 #endif
 	return 0;
-- 
2.25.1