diff options
| author | Tom Caputi <[email protected]> | 2017-12-21 12:13:06 -0500 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2017-12-21 09:13:06 -0800 |
| commit | a8b2e30685c9214ccfd0181977540e080340df4e (patch) | |
| tree | db07450d097c27b1e3d627f8ae58387cad9d0038 /tests | |
| parent | 993669a7bf17a26843630c547999be0b27483497 (diff) | |
Support re-prioritizing asynchronous prefetches
When sequential scrubs were merged, all calls to arc_read()
(including prefetch IOs) were given ZIO_PRIORITY_ASYNC_READ.
Unfortunately, this behaves badly with an existing issue where
prefetch IOs cannot be re-prioritized after the issue. The
result is that synchronous reads end up in the same vdev_queue
as the scrub IOs and can have (in some workloads) multiple
seconds of latency.
This patch incorporates 2 changes. The first ensures that all
scrub IOs are given ZIO_PRIORITY_SCRUB to allow the vdev_queue
code to differentiate between these I/Os and user prefetches.
Second, this patch introduces zio_change_priority() to provide
the missing capability to upgrade a zio's priority.
Reviewed by: George Wilson <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #6921
Closes #6926
Diffstat (limited to 'tests')
| -rwxr-xr-x | tests/zfs-tests/tests/perf/scripts/prefetch_io.sh | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/tests/zfs-tests/tests/perf/scripts/prefetch_io.sh b/tests/zfs-tests/tests/perf/scripts/prefetch_io.sh index 85e7d940a..75bf08f4b 100755 --- a/tests/zfs-tests/tests/perf/scripts/prefetch_io.sh +++ b/tests/zfs-tests/tests/perf/scripts/prefetch_io.sh @@ -41,9 +41,9 @@ function get_prefetched_demand_reads echo $demand_reads } -function get_sync_wait_for_async +function get_async_upgrade_sync { - typeset -l sync_wait=`awk '$1 == "sync_wait_for_async" \ + typeset -l sync_wait=`awk '$1 == "async_upgrade_sync" \ { print $3 }' $zfs_kstats/arcstats` echo $sync_wait @@ -59,7 +59,7 @@ poolname=$1 interval=$2 prefetch_ios=$(get_prefetch_ios) prefetched_demand_reads=$(get_prefetched_demand_reads) -sync_wait_for_async=$(get_sync_wait_for_async) +async_upgrade_sync=$(get_async_upgrade_sync) while true do @@ -73,10 +73,10 @@ do $(( $new_prefetched_demand_reads - $prefetched_demand_reads )) prefetched_demand_reads=$new_prefetched_demand_reads - new_sync_wait_for_async=$(get_sync_wait_for_async) - printf "%-24s\t%u\n" "sync_wait_for_async" \ - $(( $new_sync_wait_for_async - $sync_wait_for_async )) - sync_wait_for_async=$new_sync_wait_for_async + new_async_upgrade_sync=$(get_async_upgrade_sync) + printf "%-24s\t%u\n" "async_upgrade_sync" \ + $(( $new_async_upgrade_sync - $async_upgrade_sync )) + async_upgrade_sync=$new_async_upgrade_sync sleep $interval done |