The first patch of this series improves read randomness to avoid excessive device read cache hit under a random read pattern for a device with very few written zones. With this patch applied, on a 14TB SMR disk with only 100 zones written, random read performance results change from several thousands IOPS down to a more realistic disk-like 100 IOPS or so. The second patch cleans up zbd related declarations. The third patch fixes a small bug. Changes from v2: * Reworked first patch to simplify the I/O adjustement algorithm * Fixed typo in second patch title (forgotten in v2) * Dropped patch 4 (now fixed by changes in the first patch) * Dropped patch 5 Changes from v1: * Reworked first patch according to Bart's comments. * Fixed typo in second patch title * Added patches 3 to 5 Damien Le Moal (3): zbd: Improve read randomness zbd: Remove inexistent functions declaration zbd: Fix zbd_zone_idx() zbd.c | 61 +++++++++++++++++++++++++++++++++++++++-------------------- zbd.h | 12 ------------ 2 files changed, 40 insertions(+), 33 deletions(-) -- 2.17.1
