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| author | Hans Holmberg <hans.holmberg@cnexlabs.com> | 2018-03-30 00:04:55 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-03-30 01:29:09 +0200 |
| commit | 5d149bfabeb889b7ee5cd6491bc6d2b5b20c4abd (patch) | |
| tree | 03398b6d423681651a0181463912056226af68c8 /drivers/lightnvm/pblk.h | |
| parent | lightnvm: remove multiple groups in 1.2 data structure (diff) | |
| download | linux-5d149bfabeb889b7ee5cd6491bc6d2b5b20c4abd.tar.xz linux-5d149bfabeb889b7ee5cd6491bc6d2b5b20c4abd.zip | |
lightnvm: pblk: add padding distribution sysfs attribute
When pblk receives a sync, all data up to that point in the write buffer
must be comitted to persistent storage, and as flash memory comes with a
minimal write size there is a significant cost involved both in terms
of time for completing the sync and in terms of write amplification
padded sectors for filling up to the minimal write size.
In order to get a better understanding of the costs involved for syncs,
Add a sysfs attribute to pblk: padded_dist, showing a normalized
distribution of sectors padded. In order to facilitate measurements of
specific workloads during the lifetime of the pblk instance, the
distribution can be reset by writing 0 to the attribute.
Do this by introducing counters for each possible padding:
{0..(minimal write size - 1)} and calculate the normalized distribution
when showing the attribute.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Javier González <javier@cnexlabs.com>
Rearranged total_buckets statement in pblk_sysfs_get_padding_dist
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/lightnvm/pblk.h')
| -rw-r--r-- | drivers/lightnvm/pblk.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h index 4b7d8618631f..17e2f242f7da 100644 --- a/drivers/lightnvm/pblk.h +++ b/drivers/lightnvm/pblk.h @@ -626,12 +626,16 @@ struct pblk { u64 gc_rst_wa; u64 pad_rst_wa; + /* Counters used for calculating padding distribution */ + atomic64_t *pad_dist; /* Padding distribution buckets */ + u64 nr_flush_rst; /* Flushes reset value for pad dist.*/ + atomic64_t nr_flush; /* Number of flush/fua I/O */ + #ifdef CONFIG_NVM_DEBUG /* Non-persistent debug counters, 4kb sector I/Os */ atomic_long_t inflight_writes; /* Inflight writes (user and gc) */ atomic_long_t padded_writes; /* Sectors padded due to flush/fua */ atomic_long_t padded_wb; /* Sectors padded in write buffer */ - atomic_long_t nr_flush; /* Number of flush/fua I/O */ atomic_long_t req_writes; /* Sectors stored on write buffer */ atomic_long_t sub_writes; /* Sectors submitted from buffer */ atomic_long_t sync_writes; /* Sectors synced to media */ |