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author | Jens Axboe <axboe@fb.com> | 2016-11-09 12:36:15 -0700 |
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committer | Jens Axboe <axboe@fb.com> | 2016-11-10 13:53:32 -0700 |
commit | e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c (patch) | |
tree | 2cf40c43afdc01d953eae0098c4f8bb4d760c8d9 /include/trace | |
parent | cf43e6be865a582ba66ee4747ae27a0513f6bba1 (diff) | |
download | linux-e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c.tar.gz linux-e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c.tar.bz2 linux-e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c.zip |
blk-wbt: add general throttling mechanism
We can hook this up to the block layer, to help throttle buffered
writes.
wbt registers a few trace points that can be used to track what is
happening in the system:
wbt_lat: 259:0: latency 2446318
wbt_stat: 259:0: rmean=2446318, rmin=2446318, rmax=2446318, rsamples=1,
wmean=518866, wmin=15522, wmax=5330353, wsamples=57
wbt_step: 259:0: step down: step=1, window=72727272, background=8, normal=16, max=32
This shows a sync issue event (wbt_lat) that exceeded it's time. wbt_stat
dumps the current read/write stats for that window, and wbt_step shows a
step down event where we now scale back writes. Each trace includes the
device, 259:0 in this case.
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/trace')
-rw-r--r-- | include/trace/events/wbt.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/include/trace/events/wbt.h b/include/trace/events/wbt.h new file mode 100644 index 000000000000..3c518e455680 --- /dev/null +++ b/include/trace/events/wbt.h @@ -0,0 +1,153 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM wbt + +#if !defined(_TRACE_WBT_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_WBT_H + +#include <linux/tracepoint.h> +#include "../../../block/blk-wbt.h" + +/** + * wbt_stat - trace stats for blk_wb + * @stat: array of read/write stats + */ +TRACE_EVENT(wbt_stat, + + TP_PROTO(struct backing_dev_info *bdi, struct blk_rq_stat *stat), + + TP_ARGS(bdi, stat), + + TP_STRUCT__entry( + __array(char, name, 32) + __field(s64, rmean) + __field(u64, rmin) + __field(u64, rmax) + __field(s64, rnr_samples) + __field(s64, rtime) + __field(s64, wmean) + __field(u64, wmin) + __field(u64, wmax) + __field(s64, wnr_samples) + __field(s64, wtime) + ), + + TP_fast_assign( + strncpy(__entry->name, dev_name(bdi->dev), 32); + __entry->rmean = stat[0].mean; + __entry->rmin = stat[0].min; + __entry->rmax = stat[0].max; + __entry->rnr_samples = stat[0].nr_samples; + __entry->wmean = stat[1].mean; + __entry->wmin = stat[1].min; + __entry->wmax = stat[1].max; + __entry->wnr_samples = stat[1].nr_samples; + ), + + TP_printk("%s: rmean=%llu, rmin=%llu, rmax=%llu, rsamples=%llu, " + "wmean=%llu, wmin=%llu, wmax=%llu, wsamples=%llu\n", + __entry->name, __entry->rmean, __entry->rmin, __entry->rmax, + __entry->rnr_samples, __entry->wmean, __entry->wmin, + __entry->wmax, __entry->wnr_samples) +); + +/** + * wbt_lat - trace latency event + * @lat: latency trigger + */ +TRACE_EVENT(wbt_lat, + + TP_PROTO(struct backing_dev_info *bdi, unsigned long lat), + + TP_ARGS(bdi, lat), + + TP_STRUCT__entry( + __array(char, name, 32) + __field(unsigned long, lat) + ), + + TP_fast_assign( + strncpy(__entry->name, dev_name(bdi->dev), 32); + __entry->lat = div_u64(lat, 1000); + ), + + TP_printk("%s: latency %lluus\n", __entry->name, + (unsigned long long) __entry->lat) +); + +/** + * wbt_step - trace wb event step + * @msg: context message + * @step: the current scale step count + * @window: the current monitoring window + * @bg: the current background queue limit + * @normal: the current normal writeback limit + * @max: the current max throughput writeback limit + */ +TRACE_EVENT(wbt_step, + + TP_PROTO(struct backing_dev_info *bdi, const char *msg, + int step, unsigned long window, unsigned int bg, + unsigned int normal, unsigned int max), + + TP_ARGS(bdi, msg, step, window, bg, normal, max), + + TP_STRUCT__entry( + __array(char, name, 32) + __field(const char *, msg) + __field(int, step) + __field(unsigned long, window) + __field(unsigned int, bg) + __field(unsigned int, normal) + __field(unsigned int, max) + ), + + TP_fast_assign( + strncpy(__entry->name, dev_name(bdi->dev), 32); + __entry->msg = msg; + __entry->step = step; + __entry->window = div_u64(window, 1000); + __entry->bg = bg; + __entry->normal = normal; + __entry->max = max; + ), + + TP_printk("%s: %s: step=%d, window=%luus, background=%u, normal=%u, max=%u\n", + __entry->name, __entry->msg, __entry->step, __entry->window, + __entry->bg, __entry->normal, __entry->max) +); + +/** + * wbt_timer - trace wb timer event + * @status: timer state status + * @step: the current scale step count + * @inflight: tracked writes inflight + */ +TRACE_EVENT(wbt_timer, + + TP_PROTO(struct backing_dev_info *bdi, unsigned int status, + int step, unsigned int inflight), + + TP_ARGS(bdi, status, step, inflight), + + TP_STRUCT__entry( + __array(char, name, 32) + __field(unsigned int, status) + __field(int, step) + __field(unsigned int, inflight) + ), + + TP_fast_assign( + strncpy(__entry->name, dev_name(bdi->dev), 32); + __entry->status = status; + __entry->step = step; + __entry->inflight = inflight; + ), + + TP_printk("%s: status=%u, step=%d, inflight=%u\n", __entry->name, + __entry->status, __entry->step, __entry->inflight) +); + +#endif /* _TRACE_WBT_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> |