From: Kevin Krakauer <krakauer@google.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, edumazet@google.com, horms@kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
netdev@vger.kernel.org, pabeni@redhat.com, shuah@kernel.org
Subject: Re: [PATCH] selftests/net: deflake GRO tests and fix return value and output
Date: Tue, 25 Feb 2025 12:05:04 -0800 [thread overview]
Message-ID: <Z74icGa4rlnNafoW@google.com> (raw)
In-Reply-To: <20250224124830.7c38608a@kernel.org>
On Mon, Feb 24, 2025 at 12:48:30PM -0800, Jakub Kicinski wrote:
> With msec-long deferrals we'll flush due to jiffies change. At least
> that explains a bit. Could you maybe try lower timeouts than 1msec?
> Previously we'd just keep partially-completed packets in GRO for up
> to 1msec, now we'll delay all packet processing for 1msec, that's a lot.
Results again with each test run 1000 times:
gro_flush_timeout=50us napi_defer_hard_irqs=1 --> failed to GRO 0 times
gro_flush_timeout=100us napi_defer_hard_irqs=1 --> failed to GRO 0 times
gro_flush_timeout=50us napi_defer_hard_irqs=0 --> failed to GRO 36 times
gro_flush_timeout=100us napi_defer_hard_irqs=0 --> failed to GRO 46 times
100us with 1 defer seems to work fine and is well below the duration of
a jiffy. So we'll usually be testing the "default" GRO path and only
occasionally the jiffy-update path. I'll make these the numbers in the
revised patch unless someone thinks otherwise.
next prev parent reply other threads:[~2025-02-25 20:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-18 16:45 [PATCH] selftests/net: deflake GRO tests and fix return value and output Kevin Krakauer
2025-02-21 1:04 ` Jakub Kicinski
2025-02-23 15:19 ` Kevin Krakauer
2025-02-24 20:48 ` Jakub Kicinski
2025-02-25 20:05 ` Kevin Krakauer [this message]
2025-02-25 13:16 ` Petr Machata
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