From: Peter Zijlstra <peterz@infradead.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-kernel <linux-kernel@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH] x86/apic: reduce cache line misses in __x2apic_send_IPI_mask()
Date: Thu, 7 Oct 2021 09:29:17 +0200 [thread overview]
Message-ID: <20211007072917.GN174703@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20211007031756.345269-1-eric.dumazet@gmail.com>
On Wed, Oct 06, 2021 at 08:17:56PM -0700, Eric Dumazet wrote:
> +/* __x2apic_send_IPI_mask() possibly needs to read
> + * x86_cpu_to_logical_apicid for all online cpus in a sequential way.
> + * Using per cpu variable would cost one cache line per cpu.
> + */
Broken comment style..
> +static u32 x86_cpu_to_logical_apicid[NR_CPUS] __read_mostly;
NR_CPUS is really sad, could this at all be dynamically allocated? Say
in x2apic_cluster_probe() ?
Otherwise this looks very nice!
next prev parent reply other threads:[~2021-10-07 7:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-07 3:17 [PATCH] x86/apic: reduce cache line misses in __x2apic_send_IPI_mask() Eric Dumazet
2021-10-07 7:29 ` Peter Zijlstra [this message]
2021-10-07 14:04 ` Eric Dumazet
2021-10-07 14:06 ` Peter Zijlstra
2021-10-07 14:13 ` Eric Dumazet
2021-10-07 22:13 ` Eric Dumazet
2021-10-12 12:45 ` Peter Zijlstra
2021-10-13 18:02 ` Eric Dumazet
2021-10-15 13:26 ` Peter Zijlstra
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