qemu/include/block
Stefan Hajnoczi 82a4118694 aio: self-tune polling time
This patch is based on the algorithm for the kvm.ko halt_poll_ns
parameter in Linux.  The initial polling time is zero.

If the event loop is woken up within the maximum polling time it means
polling could be effective, so grow polling time.

If the event loop is woken up beyond the maximum polling time it means
polling is not effective, so shrink polling time.

If the event loop makes progress within the current polling time then
the sweet spot has been reached.

This algorithm adjusts the polling time so it can adapt to variations in
workloads.  The goal is to reach the sweet spot while also recognizing
when polling would hurt more than help.

Two new trace events, poll_grow and poll_shrink, are added for observing
polling time adjustment.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-13-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-01-03 16:38:50 +00:00
..
accounting.h Use scripts/clean-includes to drop redundant qemu/typedefs.h 2016-03-22 22:20:16 +01:00
aio.h aio: self-tune polling time 2017-01-03 16:38:50 +00:00
block_backup.h Backup: export interfaces for extra serialization 2016-09-13 11:00:56 +01:00
block_int.h blockjob: refactor backup_start as backup_job_create 2016-11-14 22:47:34 -05:00
block.h blockjobs: split interface into public/private, Part 1 2016-11-01 08:04:56 -04:00
blockjob_int.h blockjob: add .start field 2016-11-14 22:47:34 -05:00
blockjob.h blockjob: add block_job_start 2016-11-14 22:47:34 -05:00
dirty-bitmap.h block: More operations for meta dirty bitmap 2016-10-24 17:56:07 +02:00
nbd.h nbd: Implement NBD_CMD_WRITE_ZEROES on server 2016-11-02 09:28:56 +01:00
qapi.h block/qapi: Use blk_enable_write_cache() 2016-03-30 12:16:02 +02:00
raw-aio.h linux-aio: share one LinuxAioState within an AioContext 2016-07-18 15:09:31 +01:00
scsi.h * SCSI scanner support 2016-07-14 13:44:06 +01:00
snapshot.h include: Clean up includes 2016-02-23 12:43:05 +00:00
thread-pool.h Clean up decorations and whitespace around header guards 2016-07-12 16:20:46 +02:00
throttle-groups.h block: Move I/O throttling configuration functions to BlockBackend 2016-05-19 16:45:30 +02:00
write-threshold.h Use scripts/clean-includes to drop redundant qemu/typedefs.h 2016-03-22 22:20:16 +01:00