From: "D. Wythe" <alibuda@linux.alibaba.com >
To: Mahanta Jambigi <mjambigi@linux.ibm.com>
Cc: "D. Wythe" <alibuda@linux.alibaba.com>,
wenjia@linux.ibm.com, wintera@linux.ibm.com,
dust.li@linux.alibaba.com, tonylu@linux.alibaba.com,
guwen@linux.alibaba.com, kuba@kernel.org, davem@davemloft.net,
netdev@vger.kernel.org, linux-s390@vger.kernel.org,
linux-rdma@vger.kernel.org, leonro@nvidia.com, pabeni@redhat.com,
edumazet@google.com, sidraya@linux.ibm.com, jaka@linux.ibm.com,
oliver.yang@linux.alibaba.com
Subject: Re: [PATCH net-next v1 2/2] net/smc: reduce TX slot contention with exclusive wait
Date: Fri, 21 Aug 2026 17:19:58 +0800 [thread overview]
Message-ID: <20260821091958.GA21978@j66a10360.sqa.eu95> (raw)
In-Reply-To: <e16d16f1-029b-4d30-b393-2e9e525a2998@linux.ibm.com>
On Fri, Aug 07, 2026 at 11:15:22AM +0530, Mahanta Jambigi wrote:
>
>
> On 06/08/26 12:12 pm, D. Wythe wrote:
> > smc_wr_tx_get_free_slot() waits for a free TX slot with
> > wait_event_interruptible_timeout(). Since the wait_event family
> > enqueues waiters as non-exclusive, wake_up() may wake multiple
> > waiters even though only one can use the slot, causing
> > thundering-herd contention when slots are scarce.
>
> Have you run any performance benchmarks (e.g. redis-benchmark or uperf)
> to quantify the benefit of this change?
>
> Since the motivation is to reduce contention caused by multiple waiters
> being awakened for a single available TX slot, it would be helpful to
> see measurable results. Please share the baseline and patched throughput
> figures, and any observed throughput differences.
Yes, I ran uperf, and I have added the baseline vs patched figures to the commit
message of patch 2 in v2.
Best regards,
D. Wythe
prev parent reply other threads:[~2026-08-21 9:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-06 6:42 [PATCH net-next v1 0/2] net/smc: fix v2 slot clearing and reduce TX slot contention D. Wythe
2026-08-06 6:42 ` [PATCH net-next v1 1/2] net/smc: clear the correct v2 slot and buffer in smc_wr_tx_put_slot() D. Wythe
2026-08-06 6:42 ` [PATCH net-next v1 2/2] net/smc: reduce TX slot contention with exclusive wait D. Wythe
2026-08-07 5:45 ` Mahanta Jambigi
2026-08-21 9:19 ` D. Wythe [this message]
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