mainlining shenanigans
ddc9cc0131
This series provides updates to mlx5 ethernet driver. 1) Starting with a four patches series to optimize flow counters updates, From Vlad Buslov: ============================================== By default mlx5 driver updates cached counters each second. Update function consumes noticeable amount of CPU resources. The goal of this patch series is to optimize update function. Investigation revealed following bottlenecks in fs counters implementation: 1) Update code(scheduled each second) iterates over all counters twice. (first for finding and deleting counters that are marked for deletion, second iteration is for actually updating the counters) 2) Counters are stored in rb tree. Linear iteration over all rb tree elements(rb_next in profiling data) consumed ~65% of time spent in update function. Following optimizations were implemented: 1) Instead of just marking counters for deletion, store them in standalone list. This removes first iteration over whole counters tree. 2) Store counters in sorted list to optimize traversing them and remove calls to rb_next. First implementation of these changes caused degradation of performance, instead of improving it. Investigation revealed that there first cache line of struct mlx5_fc is full and adding anything to it causes amount of cache misses to double. To mitigate that, following refactorings were implemented: - Change 'addlist' list type from double linked to single linked. This allowes to get free space for one additional pointer that is used to store deletion list(optimization 1) - Substitute rb tree with idr. Idr is non-intrusive data structure and doesn't require adding any new members to struct mlx5_fc. Use free space that became available for double linked sorted list that is used for traversing all counters. (optimization 2) Described changes reduced CPU time spent in mlx5_fc_stats_work from 70% to 44%. (global perf profile mode) ============================================ The rest of the series are misc updates: 2) From Kamal, Move mlx5e_priv_flags into en_ethtool.c, to avoid a compilation warning. 3) From Roi Dayan, Move Q counters allocation and drop RQ to init_rx profile function to avoid allocating Q counters when not required. 4) From Shay Agroskin, Replace PTP clock lock from RW lock to seq lock. Almost double the packet rate when timestamping is active on multiple TX queues. 5) From: Natali Shechtman, set ECN for received packets using CQE indication. 6) From: Alaa Hleihel, don't set CHECKSUM_COMPLETE on SCTP packets. CHECKSUM_COMPLETE is not applicable to SCTP protocol. -----BEGIN PGP SIGNATURE----- iQEcBAABAgAGBQJbkKzcAAoJEEg/ir3gV/o+4bsIAKu61DsZZhJAXfwZ4JXI9fN7 iZ9wOPbPovTrkfRfqatcCa3CBwxM1zZ6WzbVTGGieMsUnxjp4G+LAs7m8J+cmWB2 GsxhO3lsF5iGTcEB5Q5a/TlWlUP0CiPcdNZZe6FvT2Vzil+mLAb3BZgIPKPgoyJW CmDhIOslfolBJC0s4fc+zVcWrShmKnUwHmVLhkOXpz8cfYBB1fBVGebRTZiYsvbf 8CV4buiYx0Fuq9MSnOwaMuPrUP1IB6DweNbFpg9gRd0k4mmWnoNu3l+g1Flgmd88 RtU4+5PEtZF2kNhH/LeiHRqkZ5f2cmOsIKbDZoX6xwzfYesws8jlDJpL5dIhxZA= =nxDw -----END PGP SIGNATURE----- Merge tag 'mlx5e-updates-2018-09-05' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux Saeed Mahameed says: ==================== mlx5e-updates-2018-09-05 This series provides updates to mlx5 ethernet driver. 1) Starting with a four patches series to optimize flow counters updates, From Vlad Buslov: ============================================== By default mlx5 driver updates cached counters each second. Update function consumes noticeable amount of CPU resources. The goal of this patch series is to optimize update function. Investigation revealed following bottlenecks in fs counters implementation: 1) Update code(scheduled each second) iterates over all counters twice. (first for finding and deleting counters that are marked for deletion, second iteration is for actually updating the counters) 2) Counters are stored in rb tree. Linear iteration over all rb tree elements(rb_next in profiling data) consumed ~65% of time spent in update function. Following optimizations were implemented: 1) Instead of just marking counters for deletion, store them in standalone list. This removes first iteration over whole counters tree. 2) Store counters in sorted list to optimize traversing them and remove calls to rb_next. First implementation of these changes caused degradation of performance, instead of improving it. Investigation revealed that there first cache line of struct mlx5_fc is full and adding anything to it causes amount of cache misses to double. To mitigate that, following refactorings were implemented: - Change 'addlist' list type from double linked to single linked. This allowes to get free space for one additional pointer that is used to store deletion list(optimization 1) - Substitute rb tree with idr. Idr is non-intrusive data structure and doesn't require adding any new members to struct mlx5_fc. Use free space that became available for double linked sorted list that is used for traversing all counters. (optimization 2) Described changes reduced CPU time spent in mlx5_fc_stats_work from 70% to 44%. (global perf profile mode) ============================================ The rest of the series are misc updates: 2) From Kamal, Move mlx5e_priv_flags into en_ethtool.c, to avoid a compilation warning. 3) From Roi Dayan, Move Q counters allocation and drop RQ to init_rx profile function to avoid allocating Q counters when not required. 4) From Shay Agroskin, Replace PTP clock lock from RW lock to seq lock. Almost double the packet rate when timestamping is active on multiple TX queues. 5) From: Natali Shechtman, set ECN for received packets using CQE indication. 6) From: Alaa Hleihel, don't set CHECKSUM_COMPLETE on SCTP packets. CHECKSUM_COMPLETE is not applicable to SCTP protocol. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.