From: Keith Busch <kbusch@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: bigeasy@linutronix.de, helgaas@kernel.org,
Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, hch@lst.de
Subject: Re: [PATCH 4/4] nvme/pci: Spin threaded interrupt completions
Date: Thu, 28 Nov 2019 12:58:03 +0900 [thread overview]
Message-ID: <20191128035803.GA1947@redsun51.ssa.fujisawa.hgst.com> (raw)
In-Reply-To: <20191128035139.GE3277@ming.t460p>
On Thu, Nov 28, 2019 at 11:51:39AM +0800, Ming Lei wrote:
> On Thu, Nov 28, 2019 at 12:28:43PM +0900, Keith Busch wrote:
> >
> > When you have two or more devices with queues mapped to multiple CPUs,
> > their threaded interrupt handler affinities will not share the same CPU.
>
> They still may share same CPU if there are many enough NVMe drives, the
> threaded interrupt handler actually takes the effective hard interrupt's
> affinity, which still may point to same CPU, in case of:
>
> nr_nvme_drives * nr_hw_queues > nr_cpus
Yeah, that's true. I'm just a bit constrained on devices, so having some
difficulty testing Sagi's scenario. I assume the cond_resched() provides
appropriate fairness here, but will need more time to instrument such a test.
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next prev parent reply other threads:[~2019-11-28 3:58 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 17:58 [PATCH 0/4] nvme: Threaded interrupt handling improvements Keith Busch
2019-11-27 17:58 ` [PATCH 1/4] PCI/MSI: Export __pci_msix_desc_mask_irq Keith Busch
2019-11-28 2:42 ` Sagi Grimberg
2019-11-28 3:41 ` Keith Busch
2019-11-28 7:17 ` Christoph Hellwig
2019-11-27 17:58 ` [PATCH 2/4] nvme/pci: Mask legacy and MSI in threaded handler Keith Busch
2019-11-28 3:39 ` Ming Lei
2019-11-28 3:48 ` Keith Busch
2019-11-28 3:58 ` Ming Lei
2019-11-28 4:14 ` Keith Busch
2019-11-28 8:41 ` Ming Lei
2019-11-27 17:58 ` [PATCH 3/4] nvme/pci: Mask MSIx interrupts for threaded handling Keith Busch
2019-11-28 7:19 ` Christoph Hellwig
2019-11-27 17:58 ` [PATCH 4/4] nvme/pci: Spin threaded interrupt completions Keith Busch
2019-11-28 2:46 ` Sagi Grimberg
2019-11-28 3:28 ` Keith Busch
2019-11-28 3:51 ` Ming Lei
2019-11-28 3:58 ` Keith Busch [this message]
2019-11-28 7:22 ` Christoph Hellwig
2019-11-29 9:13 ` Sebastian Andrzej Siewior
2019-11-30 18:10 ` Keith Busch
2019-12-02 1:10 ` Ming Lei
2019-12-02 1:30 ` Keith Busch
2019-12-02 16:51 ` Sebastian Andrzej Siewior
2019-11-28 7:50 ` [PATCH 0/4] nvme: Threaded interrupt handling improvements Christoph Hellwig
2019-11-28 17:59 ` Keith Busch
2019-11-29 8:30 ` Christoph Hellwig
2019-11-29 9:46 ` Sebastian Andrzej Siewior
2019-11-29 16:27 ` Keith Busch
2019-11-29 17:05 ` Sebastian Andrzej Siewior
2019-11-30 17:02 ` Keith Busch
2019-12-02 17:05 ` Sebastian Andrzej Siewior
2019-12-02 17:12 ` Christoph Hellwig
2019-12-02 18:06 ` Keith Busch
2019-12-03 7:40 ` Christoph Hellwig
2019-12-02 19:57 ` Sebastian Andrzej Siewior
2019-12-03 7:42 ` Christoph Hellwig
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