From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: Dipayaan Roy <dipayanroy@linux.microsoft.com>
Cc: <kys@microsoft.com>, <haiyangz@microsoft.com>,
<wei.liu@kernel.org>, <decui@microsoft.com>,
<andrew+netdev@lunn.ch>, <davem@davemloft.net>,
<edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
<leon@kernel.org>, <longli@microsoft.com>,
<kotaranov@microsoft.com>, <horms@kernel.org>,
<shradhagupta@linux.microsoft.com>, <ssengar@linux.microsoft.com>,
<ernis@linux.microsoft.com>, <shirazsaleem@microsoft.com>,
<linux-hyperv@vger.kernel.org>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-rdma@vger.kernel.org>,
<stephen@networkplumber.org>, <jacob.e.keller@intel.com>,
<dipayanroy@microsoft.com>, <leitao@debian.org>,
<kees@kernel.org>, <john.fastabend@gmail.com>, <hawk@kernel.org>,
<bpf@vger.kernel.org>, <daniel@iogearbox.net>, <ast@kernel.org>,
<sdf@fomichev.me>, <yury.norov@gmail.com>,
<pavan.chebbi@broadcom.com>
Subject: Re: [PATCH net-next v11 0/2] net: mana: add ethtool private flag for full-page RX buffers
Date: Wed, 1 Jul 2026 16:45:14 +0200 [thread overview]
Message-ID: <akUn+nMBrjbUts2N@boxer> (raw)
In-Reply-To: <20260701141808.461554-1-dipayanroy@linux.microsoft.com>
On Wed, Jul 01, 2026 at 07:15:44AM -0700, Dipayaan Roy wrote:
> On some ARM64 platforms with 4K PAGE_SIZE, utilizing page_pool
> fragments for allocation in the RX refill path (~2kB buffer per fragment)
> causes 15-20% throughput regression under high connection counts
> (>16 TCP streams at 180+ Gbps). Using full-page buffers on these
> platforms shows no regression and restores line-rate performance.
>
> This behavior is observed on a single platform; other platforms
> perform better with page_pool fragments, indicating this is not a
> page_pool issue but platform-specific.
>
> This series adds an ethtool private flag "full-page-rx" to let the
> user opt in to one RX buffer per page:
>
> ethtool --set-priv-flags eth0 full-page-rx on
>
> There is no behavioral change by default. The flag can be persisted
> via udev rule for affected platforms.
Were you able to track down what is the actual bottleneck on the 'broken'
platform? What is the performance of full-page approach on healthy
platforms? On changelog below you mention the frag approach 'outperforms'
the full-page one.
>
> This series depends on the following fixes now merged in net-next:
> commit 17bfe0a8c014 ("net: mana: Add NULL guards in teardown path to prevent panic on attach failure")
> commit 5b05aa36ee24 ("net: mana: Skip redundant detach on already-detached port")
>
> Changes in v11:
> - Rebased on net-next
> Changes in v10:
> - Rebased on net-next which now includes the prerequisite fixes.
> - Recovery logic in mana_set_priv_flags() leverages the idempotent
> mana_detach() from the merged fixes.
> Changes in v9:
> - Added correct tree.
> Changes in v8:
> - Fixed queue_reset_work recovery by restoring port_is_up before
> scheduling reset so the handler can properly re-attach.
> - Simplified "err && schedule_port_reset" to "schedule_port_reset".
> Changes in v7:
> - Rebased onto net-next.
> - Retained private flag approach after David Wei's testing on
> Grace (ARM64) confirmed that fragment mode outperforms
> full-page mode on other platforms, validating this is a
> single-platform workaround rather than a generic issue.
> Changes in v6:
> - Added missed maintainers.
> Changes in v5:
> - Split prep refactor into separate patch (patch 1/2)
> Changes in v4:
> - Dropping the smbios string parsing and add ethtool priv flag
> to reconfigure the queues with full page rx buffers.
> Changes in v3:
> - changed u8* to char*
> Changes in v2:
> - separate reading string index and the string, remove inline.
>
> Dipayaan Roy (2):
> net: mana: refactor mana_get_strings() and mana_get_sset_count() to
> use switch
> net: mana: force full-page RX buffers via ethtool private flag
>
> drivers/net/ethernet/microsoft/mana/mana_en.c | 22 ++-
> .../ethernet/microsoft/mana/mana_ethtool.c | 178 +++++++++++++++---
> include/net/mana/mana.h | 8 +
> 3 files changed, 177 insertions(+), 31 deletions(-)
>
> --
> 2.43.0
>
>
prev parent reply other threads:[~2026-07-01 14:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-01 14:15 [PATCH net-next v11 0/2] net: mana: add ethtool private flag for full-page RX buffers Dipayaan Roy
2026-07-01 14:15 ` [PATCH net-next v11 1/2] net: mana: refactor mana_get_strings() and mana_get_sset_count() to use switch Dipayaan Roy
2026-07-01 14:15 ` [PATCH net-next v11 2/2] net: mana: force full-page RX buffers via ethtool private flag Dipayaan Roy
2026-07-01 14:45 ` Maciej Fijalkowski [this message]
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