Re: [PATCH v3 3/3] nvme-tcp: parallelize I/O queue allocation and startup

[Hannes Reinecke <hare@suse.de>]

On 9/10/26 10:28 PM, Surabhi Gogte wrote:
> Similar to commit 2a8513091d2f ("nvme-rdma: parallelize I/O queue
> allocation and startup"), refactor nvme tcp I/O queue setup to use async
> API, combining allocation and startup into a single parallel operation
> per queue. This reduces connection and reconnection setup time when
> there are delays in establishing connections, which is especially
> important for high-core-count hosts.
> 
> Key changes:
> - Use async API to facilitate parallel calls for io queue setup.
> - Add nvme_tcp_queue_setup_ctx for propagating errors from async
>    workers.
> - Remove nvme_tcp_start_io_queues() and __nvme_tcp_alloc_io_queues();
>    their logic is folded into nvme_tcp_setup_io_queues() and
>    nvme_tcp_configure_io_queues().
> - Allocate the io tag set before the queues so that the queue range is
>    known, and only set up the reconnect grow case if the queue count
>    actually increased.
> - Serialize the cpu scan and claim in nvme_tcp_set_queue_io_cpu() with a
>    spinlock, as concurrent callers would otherwise select the same cpu.
>    The per-cpu counters no longer need to be atomics.
> 
> Testing on a 64-core host with 64 IO-queues shows nvme-tcp connection
> time reduced from 61ms to 11ms.
> 
> Signed-off-by: Surabhi Gogte <sgogte@purestorage.com>
> ---
>   drivers/nvme/host/tcp.c | 124 +++++++++++++++++++++++++---------------
>   1 file changed, 79 insertions(+), 45 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@kernel.org>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
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