2024-03-13 12:39:14

by Li Feng

Subject: [PATCH v2 1/2] nvme-tcp: Export the nvme_tcp_wq to sysfs

Make the workqueue userspace visible for easy viewing and configuration.

Signed-off-by: Li Feng <[email protected]>
---
drivers/nvme/host/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index a6d596e05602..2ec1186db0a3 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -2800,7 +2800,7 @@ static int __init nvme_tcp_init_module(void)
BUILD_BUG_ON(sizeof(struct nvme_tcp_term_pdu) != 24);

nvme_tcp_wq = alloc_workqueue("nvme_tcp_wq",
- WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
+ WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_SYSFS, 0);
if (!nvme_tcp_wq)
return -ENOMEM;

--
2.44.0

2024-03-13 12:39:27

by Li Feng

Subject: [PATCH v2 2/2] nvme/tcp: Add wq_unbound modparam for nvme_tcp_wq

The default nvme_tcp_wq will use all CPUs to process tasks. Sometimes it is
necessary to set CPU affinity to improve performance.

A new module parameter wq_unbound is added here. If set to true, users can
configure cpu affinity through
/sys/devices/virtual/workqueue/nvme_tcp_wq/cpumask.

Signed-off-by: Li Feng <[email protected]>
---
drivers/nvme/host/tcp.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 2ec1186db0a3..34a882b2ec53 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -36,6 +36,14 @@ static int so_priority;
module_param(so_priority, int, 0644);
MODULE_PARM_DESC(so_priority, "nvme tcp socket optimize priority");

+/*
+ * Use the unbound workqueue for nvme_tcp_wq, then we can set the cpu affinity
+ * from sysfs.
+ */
+static bool wq_unbound;
+module_param(wq_unbound, bool, 0644);
+MODULE_PARM_DESC(wq_unbound, "Use unbound workqueue for nvme-tcp IO context (default false)");
+
/*
* TLS handshake timeout
*/
@@ -1551,7 +1559,10 @@ static void nvme_tcp_set_queue_io_cpu(struct nvme_tcp_queue *queue)
else if (nvme_tcp_poll_queue(queue))
n = qid - ctrl->io_queues[HCTX_TYPE_DEFAULT] -
ctrl->io_queues[HCTX_TYPE_READ] - 1;
- queue->io_cpu = cpumask_next_wrap(n - 1, cpu_online_mask, -1, false);
+ if (wq_unbound)
+ queue->io_cpu = WORK_CPU_UNBOUND;
+ else
+ queue->io_cpu = cpumask_next_wrap(n - 1, cpu_online_mask, -1, false);
}

static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid)
@@ -2790,6 +2801,8 @@ static struct nvmf_transport_ops nvme_tcp_transport = {

static int __init nvme_tcp_init_module(void)
{
+ unsigned int wq_flags = WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_SYSFS;
+
BUILD_BUG_ON(sizeof(struct nvme_tcp_hdr) != 8);
BUILD_BUG_ON(sizeof(struct nvme_tcp_cmd_pdu) != 72);
BUILD_BUG_ON(sizeof(struct nvme_tcp_data_pdu) != 24);
@@ -2799,8 +2812,10 @@ static int __init nvme_tcp_init_module(void)
BUILD_BUG_ON(sizeof(struct nvme_tcp_icresp_pdu) != 128);
BUILD_BUG_ON(sizeof(struct nvme_tcp_term_pdu) != 24);

- nvme_tcp_wq = alloc_workqueue("nvme_tcp_wq",
- WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_SYSFS, 0);
+ if (wq_unbound)
+ wq_flags |= WQ_UNBOUND;
+
+ nvme_tcp_wq = alloc_workqueue("nvme_tcp_wq", wq_flags, 0);
if (!nvme_tcp_wq)
return -ENOMEM;

--
2.44.0

2024-03-17 07:30:59

by Sagi Grimberg

Subject: Re: [PATCH v2 1/2] nvme-tcp: Export the nvme_tcp_wq to sysfs

Reviewed-by: Sagi Grimberg <[email protected]>

2024-03-17 07:31:39

by Sagi Grimberg

Subject: Re: [PATCH v2 2/2] nvme/tcp: Add wq_unbound modparam for nvme_tcp_wq

Reviewed-by: Sagi Grimberg <[email protected]>

Does this get you the functionality you want Li?

2024-03-18 20:42:07

by Keith Busch

Subject: Re: [PATCH v2 1/2] nvme-tcp: Export the nvme_tcp_wq to sysfs

On Wed, Mar 13, 2024 at 08:38:09PM +0800, Li Feng wrote:
> Make the workqueue userspace visible for easy viewing and configuration.

Thanks, applied to nvme-6.9.

2024-03-18 08:56:40

by Li Feng

Subject: Re: [PATCH v2 2/2] nvme/tcp: Add wq_unbound modparam for nvme_tcp_wq

> On Mar 17, 2024, at 15:31, Sagi Grimberg <[email protected]> wrote:
>
> Reviewed-by: Sagi Grimberg <[email protected]>
>
> Does this get you the functionality you want Li?

Yes, it meets my performance needs.