Messages in this thread | | | From | Oleksij Rempel <> | Subject | [PATCH v1 0/3] reduce tty latency | Date | Thu, 10 Jan 2019 11:12:29 +0100 |
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This patch set is reducing latency on tty path. For testing I used hackbench running on all cores of 4 core system and high prioritized application sending and receiving packets over tty interface with loop-back adapter.
Results without this patches: latency histogram: 0 ... < 250 usec : 1933104 transmissions 250 ... < 500 usec : 21339 transmissions 500 ... < 750 usec : 8952 transmissions 750 ... < 1000 usec : 6226 transmissions 1000 ... < 1500 usec : 7688 transmissions 1500 ... < 2000 usec : 5236 transmissions 2000 ... < 5000 usec : 11724 transmissions 5000 ... < 10000 usec : 3588 transmissions 10000 ... < 50000 usec : 2123 transmissions 50000 ... < 1000000 usec : 20 transmissions >= 1000000 usec : 0 transmissions
Test results after this patches: min latency: 0 sec : 75 usec max latency: 0 sec : 125 usec average latency: 81 usec latency measure cycles overall: 79000000 latency histogram: 0 ... < 250 usec : 79000000 transmissions 250 ... < 500 usec : 0 transmissions 500 ... < 750 usec : 0 transmissions 750 ... < 1000 usec : 0 transmissions 1000 ... < 1500 usec : 0 transmissions 1500 ... < 2000 usec : 0 transmissions 2000 ... < 5000 usec : 0 transmissions 5000 ... < 10000 usec : 0 transmissions 10000 ... < 50000 usec : 0 transmissions 50000 ... < 1000000 usec : 0 transmissions >= 1000000 usec : 0 transmissions average no. of read calls to assemble the packet: 1
Usage of real-time patches makes no difference for test case.
Oleksij Rempel (1): drivers/tty: increase priority for tty_buffer_worker
Steven Walter (2): drivers/tty: refactor functions for flushing/queuing work drivers/tty: convert tty_port to use kthread_worker
drivers/tty/tty_buffer.c | 39 +++++++++++++++++++++++++++++++-------- drivers/tty/tty_io.c | 1 + include/linux/tty.h | 8 +++++--- 3 files changed, 37 insertions(+), 11 deletions(-)
-- 2.19.1
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