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Diffstat (limited to 'Documentation/ABI/testing/sysfs-block')
-rw-r--r-- | Documentation/ABI/testing/sysfs-block | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 5f3beda..4873c75 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -4,7 +4,7 @@ Contact: Jerome Marchand <jmarchan@redhat.com> Description: The /sys/block/<disk>/stat files displays the I/O statistics of disk <disk>. They contain 11 fields: - 1 - reads completed succesfully + 1 - reads completed successfully 2 - reads merged 3 - sectors read 4 - time spent reading (ms) @@ -128,3 +128,17 @@ Description: preferred request size for workloads where sustained throughput is desired. If no optimal I/O size is reported this file contains 0. + +What: /sys/block/<disk>/queue/nomerges +Date: January 2010 +Contact: +Description: + Standard I/O elevator operations include attempts to + merge contiguous I/Os. For known random I/O loads these + attempts will always fail and result in extra cycles + being spent in the kernel. This allows one to turn off + this behavior on one of two ways: When set to 1, complex + merge checks are disabled, but the simple one-shot merges + with the previous I/O request are enabled. When set to 2, + all merge tries are disabled. The default value is 0 - + which enables all types of merge tries. |