Add a new debug counter to measure cache hits on the read path
Signed-off-by: Javier González <javier@xxxxxxxxxxxx>
Signed-off-by: Matias Bjørling <matias@xxxxxxxxxxxx>
---
drivers/lightnvm/pblk-init.c | 1 +
drivers/lightnvm/pblk-read.c | 6 ++++++
drivers/lightnvm/pblk-sysfs.c | 3 ++-
drivers/lightnvm/pblk.h | 1 +
4 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index ae8cd6d5af8b..3ec3deff709f 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -838,6 +838,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
atomic_long_set(&pblk->sync_writes, 0);
atomic_long_set(&pblk->compl_writes, 0);
atomic_long_set(&pblk->inflight_reads, 0);
+ atomic_long_set(&pblk->cache_reads, 0);
atomic_long_set(&pblk->sync_reads, 0);
atomic_long_set(&pblk->recov_writes, 0);
atomic_long_set(&pblk->recov_writes, 0);
diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index 762c0b73cb67..91307297e444 100644
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c
@@ -76,6 +76,9 @@ static void pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
}
WARN_ON(test_and_set_bit(i, read_bitmap));
advanced_bio = 1;
+#ifdef CONFIG_NVM_DEBUG
+ atomic_long_inc(&pblk->cache_reads);
+#endif
} else {
/* Read from media non-cached sectors */
rqd->ppa_list[j++] = p;
@@ -280,6 +283,9 @@ static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd,
goto retry;
}
WARN_ON(test_and_set_bit(0, read_bitmap));
+#ifdef CONFIG_NVM_DEBUG
+ atomic_long_inc(&pblk->cache_reads);
+#endif
} else {
rqd->ppa_addr = ppa;
}
diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
index f0af1d1ceeff..3c1a586c09a2 100644
--- a/drivers/lightnvm/pblk-sysfs.c
+++ b/drivers/lightnvm/pblk-sysfs.c
@@ -294,7 +294,7 @@ static ssize_t pblk_sysfs_lines_info(struct pblk *pblk, char *page)
static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
{
return snprintf(page, PAGE_SIZE,
- "%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
+ "%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
atomic_long_read(&pblk->inflight_writes),
atomic_long_read(&pblk->inflight_reads),
atomic_long_read(&pblk->req_writes),
@@ -307,6 +307,7 @@ static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
atomic_long_read(&pblk->recov_writes),
atomic_long_read(&pblk->recov_gc_writes),
atomic_long_read(&pblk->recov_gc_reads),
+ atomic_long_read(&pblk->cache_reads),
atomic_long_read(&pblk->sync_reads));
}
#endif
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 99f3186b5288..70b65d308dea 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -513,6 +513,7 @@ struct pblk {
atomic_long_t sync_writes; /* Sectors synced to media */
atomic_long_t compl_writes; /* Sectors completed in write bio */
atomic_long_t inflight_reads; /* Inflight sector read requests */
+ atomic_long_t cache_reads; /* Read requests that hit the cache */
atomic_long_t sync_reads; /* Completed sector read requests */
atomic_long_t recov_writes; /* Sectors submitted from recovery */
atomic_long_t recov_gc_writes; /* Sectors submitted from write GC */
--
2.7.4
