* Re: [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode
2025-12-02 12:23 [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode Chwee-Lin Choong
@ 2025-12-02 8:35 ` Loktionov, Aleksandr
2025-12-02 16:45 ` Simon Horman
2025-12-02 17:34 ` Paul Menzel
2 siblings, 0 replies; 4+ messages in thread
From: Loktionov, Aleksandr @ 2025-12-02 8:35 UTC (permalink / raw)
To: Choong, Chwee Lin, Nguyen, Anthony L, Kitszel, Przemyslaw,
Andrew Lunn, David S . Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni
Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Bouska, JacquelynnX, Bouska, Zdenek,
Faizal Rahim
> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> Of Chwee-Lin Choong
> Sent: Tuesday, December 2, 2025 1:24 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@intel.com>; Andrew Lunn
> <andrew+netdev@lunn.ch>; David S . Miller <davem@davemloft.net>; Eric
> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>
> Cc: intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; Bouska; Bouska, Zdenek
> <zdenek.bouska@siemens.com>; Faizal Rahim
> <faizal.abdul.rahim@linux.intel.com>
> Subject: [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet
> buffer per queue for TSN mode
>
> Update IGC_TXPBSIZE_TSN to allocate 5KB per TX queue (TXQ0-TXQ3) as
> recommended in I225/I226 SW User Manual Section 7.5.4 for TSN
> operation.
>
> Fixes: 0d58cdc902da ("igc: optimize TX packet buffer utilization for
> TSN mode")
> Reported-by: Bouska, Zdenek <zdenek.bouska@siemens.com>
> Closes:
> https://lore.kernel.org/netdev/AS1PR10MB5675DBFE7CE5F2A9336ABFA4EBEAA@
> AS1PR10MB5675.EURPRD10.PROD.OUTLOOK.COM/
> Signed-off-by: Chwee-Lin Choong <chwee.lin.choong@intel.com>
> ---
> drivers/net/ethernet/intel/igc/igc_defines.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h
> b/drivers/net/ethernet/intel/igc/igc_defines.h
> index 498ba1522ca4..9482ab11f050 100644
> --- a/drivers/net/ethernet/intel/igc/igc_defines.h
> +++ b/drivers/net/ethernet/intel/igc/igc_defines.h
> @@ -443,9 +443,10 @@
> #define IGC_TXPBSIZE_DEFAULT ( \
> IGC_TXPB0SIZE(20) | IGC_TXPB1SIZE(0) | IGC_TXPB2SIZE(0) | \
> IGC_TXPB3SIZE(0) | IGC_OS2BMCPBSIZE(4))
> +/* TSN value following I225/I226 SW User Manual Section 7.5.4 */
> #define IGC_TXPBSIZE_TSN ( \
> - IGC_TXPB0SIZE(7) | IGC_TXPB1SIZE(7) | IGC_TXPB2SIZE(7) | \
> - IGC_TXPB3SIZE(7) | IGC_OS2BMCPBSIZE(4))
> + IGC_TXPB0SIZE(5) | IGC_TXPB1SIZE(5) | IGC_TXPB2SIZE(5) | \
> + IGC_TXPB3SIZE(5) | IGC_OS2BMCPBSIZE(4))
>
> #define IGC_DTXMXPKTSZ_TSN 0x19 /* 1600 bytes of max TX DMA packet
> size */
> #define IGC_DTXMXPKTSZ_DEFAULT 0x98 /* 9728-byte Jumbo frames */
> --
> 2.43.0
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode
2025-12-02 12:23 [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode Chwee-Lin Choong
2025-12-02 8:35 ` Loktionov, Aleksandr
@ 2025-12-02 16:45 ` Simon Horman
2025-12-02 17:34 ` Paul Menzel
2 siblings, 0 replies; 4+ messages in thread
From: Simon Horman @ 2025-12-02 16:45 UTC (permalink / raw)
To: Chwee-Lin Choong
Cc: Tony Nguyen, Przemek Kitszel, Andrew Lunn, David S . Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, intel-wired-lan,
netdev, linux-kernel, Bouska, Zdenek, Faizal Rahim
On Tue, Dec 02, 2025 at 08:23:51PM +0800, Chwee-Lin Choong wrote:
> Update IGC_TXPBSIZE_TSN to allocate 5KB per TX queue (TXQ0-TXQ3)
> as recommended in I225/I226 SW User Manual Section 7.5.4 for TSN
> operation.
>
> Fixes: 0d58cdc902da ("igc: optimize TX packet buffer utilization for TSN mode")
> Reported-by: Bouska, Zdenek <zdenek.bouska@siemens.com>
> Closes: https://lore.kernel.org/netdev/AS1PR10MB5675DBFE7CE5F2A9336ABFA4EBEAA@AS1PR10MB5675.EURPRD10.PROD.OUTLOOK.COM/
> Signed-off-by: Chwee-Lin Choong <chwee.lin.choong@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode
2025-12-02 12:23 [Intel-wired-lan] [PATCH iwl-net v1] igc: Use 5KB TX packet buffer per queue for TSN mode Chwee-Lin Choong
2025-12-02 8:35 ` Loktionov, Aleksandr
2025-12-02 16:45 ` Simon Horman
@ 2025-12-02 17:34 ` Paul Menzel
2 siblings, 0 replies; 4+ messages in thread
From: Paul Menzel @ 2025-12-02 17:34 UTC (permalink / raw)
To: Chwee-Lin Choong
Cc: Tony Nguyen, Przemek Kitszel, Andrew Lunn, David S . Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, intel-wired-lan,
netdev, linux-kernel, Zdenek Bouska, Faizal Rahim
Dear Chwee-Lin,
Thank you for your patch.
(Just a heads-up, that Zdenek’s email address was not properly quoted in
the Cc: list.)
In the summary you could be more specific to say, that you *decrease*
the size.
Am 02.12.25 um 13:23 schrieb Chwee-Lin Choong:
> Update IGC_TXPBSIZE_TSN to allocate 5KB per TX queue (TXQ0-TXQ3)
> as recommended in I225/I226 SW User Manual Section 7.5.4 for TSN
> operation.
Please elaborate on the problem (mention the 7 KB size and hangs), and
maybe Faizal remembers why they chose 7 KB.
Also, are there any performance drawbacks. (I know that avoiding hangs
tops that, but it would be good to know.)
> Fixes: 0d58cdc902da ("igc: optimize TX packet buffer utilization for TSN mode")
> Reported-by: Zdenek Bouska <zdenek.bouska@siemens.com>
> Closes: https://lore.kernel.org/netdev/AS1PR10MB5675DBFE7CE5F2A9336ABFA4EBEAA@AS1PR10MB5675.EURPRD10.PROD.OUTLOOK.COM/
> Signed-off-by: Chwee-Lin Choong <chwee.lin.choong@intel.com>
> ---
> drivers/net/ethernet/intel/igc/igc_defines.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
> index 498ba1522ca4..9482ab11f050 100644
> --- a/drivers/net/ethernet/intel/igc/igc_defines.h
> +++ b/drivers/net/ethernet/intel/igc/igc_defines.h
> @@ -443,9 +443,10 @@
> #define IGC_TXPBSIZE_DEFAULT ( \
> IGC_TXPB0SIZE(20) | IGC_TXPB1SIZE(0) | IGC_TXPB2SIZE(0) | \
> IGC_TXPB3SIZE(0) | IGC_OS2BMCPBSIZE(4))
> +/* TSN value following I225/I226 SW User Manual Section 7.5.4 */
> #define IGC_TXPBSIZE_TSN ( \
> - IGC_TXPB0SIZE(7) | IGC_TXPB1SIZE(7) | IGC_TXPB2SIZE(7) | \
> - IGC_TXPB3SIZE(7) | IGC_OS2BMCPBSIZE(4))
> + IGC_TXPB0SIZE(5) | IGC_TXPB1SIZE(5) | IGC_TXPB2SIZE(5) | \
> + IGC_TXPB3SIZE(5) | IGC_OS2BMCPBSIZE(4))
Reading the commit message of commit 0d58cdc902da ("igc: optimize TX
packet buffer utilization for TSN mode"), it says, that the goal is to
split up 32 KB. What is happening to the 8 KB that are freed up now?
> #define IGC_DTXMXPKTSZ_TSN 0x19 /* 1600 bytes of max TX DMA packet size */
> #define IGC_DTXMXPKTSZ_DEFAULT 0x98 /* 9728-byte Jumbo frames */
With a more elaborate commit message, feel free to add:
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Kind regards,
Paul
^ permalink raw reply [flat|nested] 4+ messages in thread