From: Florian Westphal <fw@strlen.de>
To: lirongqing <lirongqing@baidu.com>
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, coreteam@netfilter.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] netfilter: conntrack: Reduce cond_resched frequency in gc_worker
Date: Tue, 14 Oct 2025 15:06:42 +0200 [thread overview]
Message-ID: <aO5K4mICGHVNlkHJ@strlen.de> (raw)
In-Reply-To: <20251014115103.2678-1-lirongqing@baidu.com>
lirongqing <lirongqing@baidu.com> wrote:
> From: Li RongQing <lirongqing@baidu.com>
>
> 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.
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?
next prev parent reply other threads:[~2025-10-14 13:06 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 [this message]
2025-10-15 1:56 ` [????] " Li,Rongqing
2025-10-15 11:06 ` Florian Westphal
2025-10-15 11:49 ` Peter Zijlstra
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