| Message ID | 1517918090-25321-1-git-send-email-hans.ml.holmberg@owltronix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/06/2018 12:54 PM, hans.ml.holmberg@owltronix.com wrote: > From: Hans Holmberg <hans.holmberg@cnexlabs.com> > > 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> > --- > > Changes since V1: > > * Picked up Matias rearrengment of the total_buckets_statement > * Fixed build problems reported by kbuild on i386 by using sector_div > instead of / when calculating the padding distribution and turning > nr_flush into atomic64_t (which makes more sense anyway) > > drivers/lightnvm/pblk-init.c | 16 +++++++- > drivers/lightnvm/pblk-rb.c | 17 +++++---- > drivers/lightnvm/pblk-sysfs.c | 86 ++++++++++++++++++++++++++++++++++++++++++- > drivers/lightnvm/pblk.h | 6 ++- > 4 files changed, 112 insertions(+), 13 deletions(-) > > diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c > index 7eedc5d..bf9bc31 100644 > --- a/drivers/lightnvm/pblk-init.c > +++ b/drivers/lightnvm/pblk-init.c > @@ -921,6 +921,7 @@ static void pblk_free(struct pblk *pblk) > { > pblk_luns_free(pblk); > pblk_lines_free(pblk); > + kfree(pblk->pad_dist); > pblk_line_meta_free(pblk); > pblk_core_free(pblk); > pblk_l2p_free(pblk); > @@ -998,11 +999,13 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk, > pblk->pad_rst_wa = 0; > pblk->gc_rst_wa = 0; > > + atomic64_set(&pblk->nr_flush, 0); > + pblk->nr_flush_rst = 0; > + > #ifdef CONFIG_NVM_DEBUG > atomic_long_set(&pblk->inflight_writes, 0); > atomic_long_set(&pblk->padded_writes, 0); > atomic_long_set(&pblk->padded_wb, 0); > - atomic_long_set(&pblk->nr_flush, 0); > atomic_long_set(&pblk->req_writes, 0); > atomic_long_set(&pblk->sub_writes, 0); > atomic_long_set(&pblk->sync_writes, 0); > @@ -1034,10 +1037,17 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk, > goto fail_free_luns; > } > > + pblk->pad_dist = kzalloc((pblk->min_write_pgs - 1) * sizeof(atomic64_t), > + GFP_KERNEL); > + if (!pblk->pad_dist) { > + ret = -ENOMEM; > + goto fail_free_line_meta; > + } > + > ret = pblk_core_init(pblk); > if (ret) { > pr_err("pblk: could not initialize core\n"); > - goto fail_free_line_meta; > + goto fail_free_pad_dist; > } > > ret = pblk_l2p_init(pblk); > @@ -1097,6 +1107,8 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk, > pblk_l2p_free(pblk); > fail_free_core: > pblk_core_free(pblk); > +fail_free_pad_dist: > + kfree(pblk->pad_dist); > fail_free_line_meta: > pblk_line_meta_free(pblk); > fail_free_luns: > diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c > index 7044b55..8b14340 100644 > --- a/drivers/lightnvm/pblk-rb.c > +++ b/drivers/lightnvm/pblk-rb.c > @@ -437,9 +437,7 @@ static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries, > if (bio->bi_opf & REQ_PREFLUSH) { > struct pblk *pblk = container_of(rb, struct pblk, rwb); > > -#ifdef CONFIG_NVM_DEBUG > - atomic_long_inc(&pblk->nr_flush); > -#endif > + atomic64_inc(&pblk->nr_flush); > if (pblk_rb_flush_point_set(&pblk->rwb, bio, mem)) > *io_ret = NVM_IO_OK; > } > @@ -620,14 +618,17 @@ unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd, > pr_err("pblk: could not pad page in write bio\n"); > return NVM_IO_ERR; > } > - } > > - atomic64_add(pad, &((struct pblk *) > - (container_of(rb, struct pblk, rwb)))->pad_wa); > + if (pad < pblk->min_write_pgs) > + atomic64_inc(&pblk->pad_dist[pad - 1]); > + else > + pr_warn("pblk: padding more than min. sectors\n"); > + > + atomic64_add(pad, &pblk->pad_wa); > + } > > #ifdef CONFIG_NVM_DEBUG > - atomic_long_add(pad, &((struct pblk *) > - (container_of(rb, struct pblk, rwb)))->padded_writes); > + atomic_long_add(pad, &pblk->padded_writes); > #endif > > return NVM_IO_OK; > diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c > index 4804bbd..1680ce0 100644 > --- a/drivers/lightnvm/pblk-sysfs.c > +++ b/drivers/lightnvm/pblk-sysfs.c > @@ -341,15 +341,61 @@ static ssize_t pblk_sysfs_get_write_amp_trip(struct pblk *pblk, char *page) > atomic64_read(&pblk->pad_wa) - pblk->pad_rst_wa, page); > } > > +static long long bucket_percentage(unsigned long long bucket, > + unsigned long long total) > +{ > + int p = bucket * 100; > + > + sector_div(p, total); > + return p; > +} > + > +static ssize_t pblk_sysfs_get_padding_dist(struct pblk *pblk, char *page) > +{ > + int sz = 0; > + unsigned long long total; > + unsigned long long total_buckets = 0; > + int buckets = pblk->min_write_pgs - 1; > + int i; > + > + total = atomic64_read(&pblk->nr_flush) - pblk->nr_flush_rst; > + if (!total) { > + for (i = 0; i < (buckets + 1); i++) > + sz += snprintf(page + sz, PAGE_SIZE - sz, > + "%d:0 ", i); > + sz += snprintf(page + sz, PAGE_SIZE - sz, "\n"); > + > + return sz; > + } > + > + for (i = 0; i < buckets; i++) > + total_buckets += atomic64_read(&pblk->pad_dist[i]); > + > + sz += snprintf(page + sz, PAGE_SIZE - sz, "0:%lld%% ", > + bucket_percentage(total - total_buckets, total)); > + > + for (i = 0; i < buckets; i++) { > + unsigned long long p; > + > + p = bucket_percentage(atomic64_read(&pblk->pad_dist[i]), > + total); > + sz += snprintf(page + sz, PAGE_SIZE - sz, "%d:%lld%% ", > + i + 1, p); > + } > + sz += snprintf(page + sz, PAGE_SIZE - sz, "\n"); > + > + return sz; > +} > + > #ifdef CONFIG_NVM_DEBUG > 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%ld\t%llu\t%ld\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), > - atomic_long_read(&pblk->nr_flush), > + (u64)atomic64_read(&pblk->nr_flush), > atomic_long_read(&pblk->padded_writes), > atomic_long_read(&pblk->padded_wb), > atomic_long_read(&pblk->sub_writes), > @@ -427,6 +473,32 @@ static ssize_t pblk_sysfs_set_write_amp_trip(struct pblk *pblk, > } > > > +static ssize_t pblk_sysfs_set_padding_dist(struct pblk *pblk, > + const char *page, size_t len) > +{ > + size_t c_len; > + int reset_value; > + int buckets = pblk->min_write_pgs - 1; > + int i; > + > + c_len = strcspn(page, "\n"); > + if (c_len >= len) > + return -EINVAL; > + > + if (kstrtouint(page, 0, &reset_value)) > + return -EINVAL; > + > + if (reset_value != 0) > + return -EINVAL; > + > + for (i = 0; i < buckets; i++) > + atomic64_set(&pblk->pad_dist[i], 0); > + > + pblk->nr_flush_rst = atomic64_read(&pblk->nr_flush); > + > + return len; > +} > + > static struct attribute sys_write_luns = { > .name = "write_luns", > .mode = 0444, > @@ -487,6 +559,11 @@ static struct attribute sys_write_amp_trip = { > .mode = 0644, > }; > > +static struct attribute sys_padding_dist = { > + .name = "padding_dist", > + .mode = 0644, > +}; > + > #ifdef CONFIG_NVM_DEBUG > static struct attribute sys_stats_debug_attr = { > .name = "stats", > @@ -507,6 +584,7 @@ static struct attribute *pblk_attrs[] = { > &sys_lines_info_attr, > &sys_write_amp_mileage, > &sys_write_amp_trip, > + &sys_padding_dist, > #ifdef CONFIG_NVM_DEBUG > &sys_stats_debug_attr, > #endif > @@ -540,6 +618,8 @@ static ssize_t pblk_sysfs_show(struct kobject *kobj, struct attribute *attr, > return pblk_sysfs_get_write_amp_mileage(pblk, buf); > else if (strcmp(attr->name, "write_amp_trip") == 0) > return pblk_sysfs_get_write_amp_trip(pblk, buf); > + else if (strcmp(attr->name, "padding_dist") == 0) > + return pblk_sysfs_get_padding_dist(pblk, buf); > #ifdef CONFIG_NVM_DEBUG > else if (strcmp(attr->name, "stats") == 0) > return pblk_sysfs_stats_debug(pblk, buf); > @@ -558,6 +638,8 @@ static ssize_t pblk_sysfs_store(struct kobject *kobj, struct attribute *attr, > return pblk_sysfs_set_sec_per_write(pblk, buf, len); > else if (strcmp(attr->name, "write_amp_trip") == 0) > return pblk_sysfs_set_write_amp_trip(pblk, buf, len); > + else if (strcmp(attr->name, "padding_dist") == 0) > + return pblk_sysfs_set_padding_dist(pblk, buf, len); > return 0; > } > > diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h > index 4b7d861..17e2f24 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 */ > Thanks Hans. Applied for 4.17.
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c index 7eedc5d..bf9bc31 100644 --- a/drivers/lightnvm/pblk-init.c +++ b/drivers/lightnvm/pblk-init.c @@ -921,6 +921,7 @@ static void pblk_free(struct pblk *pblk) { pblk_luns_free(pblk); pblk_lines_free(pblk); + kfree(pblk->pad_dist); pblk_line_meta_free(pblk); pblk_core_free(pblk); pblk_l2p_free(pblk); @@ -998,11 +999,13 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk, pblk->pad_rst_wa = 0; pblk->gc_rst_wa = 0; + atomic64_set(&pblk->nr_flush, 0); + pblk->nr_flush_rst = 0; + #ifdef CONFIG_NVM_DEBUG atomic_long_set(&pblk->inflight_writes, 0); atomic_long_set(&pblk->padded_writes, 0); atomic_long_set(&pblk->padded_wb, 0); - atomic_long_set(&pblk->nr_flush, 0); atomic_long_set(&pblk->req_writes, 0); atomic_long_set(&pblk->sub_writes, 0); atomic_long_set(&pblk->sync_writes, 0); @@ -1034,10 +1037,17 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk, goto fail_free_luns; } + pblk->pad_dist = kzalloc((pblk->min_write_pgs - 1) * sizeof(atomic64_t), + GFP_KERNEL); + if (!pblk->pad_dist) { + ret = -ENOMEM; + goto fail_free_line_meta; + } + ret = pblk_core_init(pblk); if (ret) { pr_err("pblk: could not initialize core\n"); - goto fail_free_line_meta; + goto fail_free_pad_dist; } ret = pblk_l2p_init(pblk); @@ -1097,6 +1107,8 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk, pblk_l2p_free(pblk); fail_free_core: pblk_core_free(pblk); +fail_free_pad_dist: + kfree(pblk->pad_dist); fail_free_line_meta: pblk_line_meta_free(pblk); fail_free_luns: diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c index 7044b55..8b14340 100644 --- a/drivers/lightnvm/pblk-rb.c +++ b/drivers/lightnvm/pblk-rb.c @@ -437,9 +437,7 @@ static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries, if (bio->bi_opf & REQ_PREFLUSH) { struct pblk *pblk = container_of(rb, struct pblk, rwb); -#ifdef CONFIG_NVM_DEBUG - atomic_long_inc(&pblk->nr_flush); -#endif + atomic64_inc(&pblk->nr_flush); if (pblk_rb_flush_point_set(&pblk->rwb, bio, mem)) *io_ret = NVM_IO_OK; } @@ -620,14 +618,17 @@ unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd, pr_err("pblk: could not pad page in write bio\n"); return NVM_IO_ERR; } - } - atomic64_add(pad, &((struct pblk *) - (container_of(rb, struct pblk, rwb)))->pad_wa); + if (pad < pblk->min_write_pgs) + atomic64_inc(&pblk->pad_dist[pad - 1]); + else + pr_warn("pblk: padding more than min. sectors\n"); + + atomic64_add(pad, &pblk->pad_wa); + } #ifdef CONFIG_NVM_DEBUG - atomic_long_add(pad, &((struct pblk *) - (container_of(rb, struct pblk, rwb)))->padded_writes); + atomic_long_add(pad, &pblk->padded_writes); #endif return NVM_IO_OK; diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c index 4804bbd..1680ce0 100644 --- a/drivers/lightnvm/pblk-sysfs.c +++ b/drivers/lightnvm/pblk-sysfs.c @@ -341,15 +341,61 @@ static ssize_t pblk_sysfs_get_write_amp_trip(struct pblk *pblk, char *page) atomic64_read(&pblk->pad_wa) - pblk->pad_rst_wa, page); } +static long long bucket_percentage(unsigned long long bucket, + unsigned long long total) +{ + int p = bucket * 100; + + sector_div(p, total); + return p; +} + +static ssize_t pblk_sysfs_get_padding_dist(struct pblk *pblk, char *page) +{ + int sz = 0; + unsigned long long total; + unsigned long long total_buckets = 0; + int buckets = pblk->min_write_pgs - 1; + int i; + + total = atomic64_read(&pblk->nr_flush) - pblk->nr_flush_rst; + if (!total) { + for (i = 0; i < (buckets + 1); i++) + sz += snprintf(page + sz, PAGE_SIZE - sz, + "%d:0 ", i); + sz += snprintf(page + sz, PAGE_SIZE - sz, "\n"); + + return sz; + } + + for (i = 0; i < buckets; i++) + total_buckets += atomic64_read(&pblk->pad_dist[i]); + + sz += snprintf(page + sz, PAGE_SIZE - sz, "0:%lld%% ", + bucket_percentage(total - total_buckets, total)); + + for (i = 0; i < buckets; i++) { + unsigned long long p; + + p = bucket_percentage(atomic64_read(&pblk->pad_dist[i]), + total); + sz += snprintf(page + sz, PAGE_SIZE - sz, "%d:%lld%% ", + i + 1, p); + } + sz += snprintf(page + sz, PAGE_SIZE - sz, "\n"); + + return sz; +} + #ifdef CONFIG_NVM_DEBUG 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%ld\t%llu\t%ld\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), - atomic_long_read(&pblk->nr_flush), + (u64)atomic64_read(&pblk->nr_flush), atomic_long_read(&pblk->padded_writes), atomic_long_read(&pblk->padded_wb), atomic_long_read(&pblk->sub_writes), @@ -427,6 +473,32 @@ static ssize_t pblk_sysfs_set_write_amp_trip(struct pblk *pblk, } +static ssize_t pblk_sysfs_set_padding_dist(struct pblk *pblk, + const char *page, size_t len) +{ + size_t c_len; + int reset_value; + int buckets = pblk->min_write_pgs - 1; + int i; + + c_len = strcspn(page, "\n"); + if (c_len >= len) + return -EINVAL; + + if (kstrtouint(page, 0, &reset_value)) + return -EINVAL; + + if (reset_value != 0) + return -EINVAL; + + for (i = 0; i < buckets; i++) + atomic64_set(&pblk->pad_dist[i], 0); + + pblk->nr_flush_rst = atomic64_read(&pblk->nr_flush); + + return len; +} + static struct attribute sys_write_luns = { .name = "write_luns", .mode = 0444, @@ -487,6 +559,11 @@ static struct attribute sys_write_amp_trip = { .mode = 0644, }; +static struct attribute sys_padding_dist = { + .name = "padding_dist", + .mode = 0644, +}; + #ifdef CONFIG_NVM_DEBUG static struct attribute sys_stats_debug_attr = { .name = "stats", @@ -507,6 +584,7 @@ static struct attribute *pblk_attrs[] = { &sys_lines_info_attr, &sys_write_amp_mileage, &sys_write_amp_trip, + &sys_padding_dist, #ifdef CONFIG_NVM_DEBUG &sys_stats_debug_attr, #endif @@ -540,6 +618,8 @@ static ssize_t pblk_sysfs_show(struct kobject *kobj, struct attribute *attr, return pblk_sysfs_get_write_amp_mileage(pblk, buf); else if (strcmp(attr->name, "write_amp_trip") == 0) return pblk_sysfs_get_write_amp_trip(pblk, buf); + else if (strcmp(attr->name, "padding_dist") == 0) + return pblk_sysfs_get_padding_dist(pblk, buf); #ifdef CONFIG_NVM_DEBUG else if (strcmp(attr->name, "stats") == 0) return pblk_sysfs_stats_debug(pblk, buf); @@ -558,6 +638,8 @@ static ssize_t pblk_sysfs_store(struct kobject *kobj, struct attribute *attr, return pblk_sysfs_set_sec_per_write(pblk, buf, len); else if (strcmp(attr->name, "write_amp_trip") == 0) return pblk_sysfs_set_write_amp_trip(pblk, buf, len); + else if (strcmp(attr->name, "padding_dist") == 0) + return pblk_sysfs_set_padding_dist(pblk, buf, len); return 0; } diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h index 4b7d861..17e2f24 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 */