linux_dsm_epyc7002/include/trace/events/wbt.h
Jens Axboe e34cbd3074 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>
2016-11-10 13:53:32 -07:00

154 lines
3.7 KiB
C

#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>