From: Juergen Gross <jgross@suse.com>
To: johnnyaiai <arafatms@outlook.com>
Cc: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
johnnyaiai@tencent.com, linux-kernel@vger.kernel.org,
mingo@redhat.com, tglx@linutronix.de,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] locking/paravirt: Fix performance regression on core bonded vCPU
Date: Thu, 3 Nov 2022 15:09:08 +0100 [thread overview]
Message-ID: <1472097d-327f-ac46-acf5-76ef3571922a@suse.com> (raw)
In-Reply-To: <MEYP282MB4026FF84EBFFBEB36C9E1682C3389@MEYP282MB4026.AUSP282.PROD.OUTLOOK.COM>
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On 03.11.22 14:58, johnnyaiai wrote:
> Thanks for reply! I think nopvspin parameters controls
> pvspinlock or native spinlock. a vm guest always running
> on virtspin wheather nopvspin sets or not when EXITS_HALT
> not supported by hypervisor. So provide a missing parameter
> 'novirtspin'.
Your patch is doing:
static_branch_disable(&virt_spin_lock_key);
in case your parameter has been specified.
When running as Xen guest the related coding is doing:
static_branch_disable(&virt_spin_lock_key);
Only when running as KVM guest there is a difference, but this could be changed
by modifying kvm_spinlock_init().
Having two parameters with the same or very similar semantics is not a good
idea IMO.
Juergen
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next prev parent reply other threads:[~2022-11-03 14:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-03 12:13 johnnyaiai
2022-11-03 13:22 ` Juergen Gross
2022-11-03 13:58 ` johnnyaiai
2022-11-03 14:09 ` Juergen Gross [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-11-03 12:10 johnnyaiai
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