From 2a3e58841b11be2bfe9dfd729988ad1ecf788d1a Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 25 Sep 2019 16:03:35 -0700 Subject: [PATCH] iocost: bump up default latency targets for hard disks commit 7afcccafa59fb63b58f863a6c5e603a34625955b upstream. The default hard disk param sets latency targets at 50ms. As the default target percentiles are zero, these don't directly regulate vrate; however, they're still used to calculate the period length - 100ms in this case. This is excessively low. A SATA drive with QD32 saturated with random IOs can easily reach avg completion latency of several hundred msecs. A period duration which is substantially lower than avg completion latency can lead to wildly fluctuating vrate. Let's bump up the default latency targets to 250ms so that the period duration is sufficiently long. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe Signed-off-by: Jiufei Xue Reviewed-by: Joseph Qi --- block/blk-iocost.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 9435310e250c..4e10c78ed18f 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -529,8 +529,8 @@ struct iocg_wake_ctx { static const struct ioc_params autop[] = { [AUTOP_HDD] = { .qos = { - [QOS_RLAT] = 50000, /* 50ms */ - [QOS_WLAT] = 50000, + [QOS_RLAT] = 250000, /* 250ms */ + [QOS_WLAT] = 250000, [QOS_MIN] = VRATE_MIN_PPM, [QOS_MAX] = VRATE_MAX_PPM, }, -- GitLab