From: "Li,Rongqing" <lirongqing@baidu.com>
To: Florian Westphal <fw@strlen.de>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@netfilter.org>,
Phil Sutter <phil@nwl.cc>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
"netfilter-devel@vger.kernel.org"
<netfilter-devel@vger.kernel.org>,
"coreteam@netfilter.org" <coreteam@netfilter.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [????] Re: [PATCH net-next] netfilter: conntrack: Reduce cond_resched frequency in gc_worker
Date: Wed, 15 Oct 2025 01:56:35 +0000 [thread overview]
Message-ID: <13de94827815469193e10d6fb0c0d45b@baidu.com> (raw)
In-Reply-To: <aO5K4mICGHVNlkHJ@strlen.de>
> > The current implementation calls cond_resched() in every iteration of
> > the garbage collection loop. This creates some overhead when
> > processing large conntrack tables with billions of entries, as each
> > cond_resched() invocation involves scheduler operations.
> >
> > To reduce this overhead, implement a time-based throttling mechanism
> > that calls cond_resched() at most once per millisecond. This maintains
> > system responsiveness while minimizing scheduler contention.
> >
> > gc_worker() with hashsize=10000 shows measurable improvement:
> >
> > Before: 7114.274us
> > After: 5993.518us (15.8% reduction)
>
> I dislike this, I have never seen this pattern.
>
This patch is similar as
commit 271557de7cbfdecb08e89ae1ca74647ceb57224f
xfs: reduce the rate of cond_resched calls inside scrub
> Whole point of cond_resched() is to let scheduler decide.
>
> Maybe it would be better to move gc_worker off to its own work queue
> (create_workqueue()) instead of reusing system wq so one can tune the
> priority instead?
I am fine to move gc_worker to its own work queue
Thanks
-Li
next prev parent reply other threads:[~2025-10-15 1:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-14 11:51 [PATCH net-next] netfilter: conntrack: Reduce cond_resched frequency in gc_worker lirongqing
2025-10-14 13:06 ` Florian Westphal
2025-10-15 1:56 ` Li,Rongqing [this message]
2025-10-15 11:06 ` Florian Westphal
2025-10-15 11:49 ` Peter Zijlstra
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