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/*
* Copyright © 2020 Google, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef _U_TRACE_H
#define _U_TRACE_H
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "util/u_queue.h"
/* A trace mechanism (very) loosely inspired by the linux kernel tracepoint
* mechanism, in that it allows for defining driver specific (or common)
* tracepoints, which generate 'trace_$name()' functions that can be
* called at various points in commandstream emit.
*
* Currently a printf backend is implemented, but the expectation is to
* also implement a perfetto backend for shipping out traces to a tool like
* AGI.
*
* Notable differences:
*
* - GPU timestamps! A driver provided callback is used to emit timestamps
* to a buffer. At a later point in time (when stalling to wait for the
* GPU is not required), the timestamps are re-united with the trace
* payload. This makes the trace mechanism suitable for profiling.
*
* - Instead of a systemwide trace ringbuffer, buffering of un-retired
* tracepoints is split into two stages. Traces are emitted to a
* 'u_trace' instance, and at a later time flushed to a 'u_trace_context'
* instance. This avoids the requirement that commandstream containing
* tracepoints is emitted in the same order as it is generated.
*
* If the hw has multiple parallel "engines" (for example, 3d/blit/compute)
* then a `u_trace_context` per-engine should be used.
*
* - Unlike kernel tracepoints, u_trace tracepoints are defined in py
* from which header and src files are generated. Since we already have
* a build dependency on python+mako, this gives more flexibility than
* clunky preprocessor macro magic.
*
*/
struct u_trace_context;
struct u_trace;
struct u_trace_chunk;
struct pipe_resource;
/**
* Special reserved value to indicate that no timestamp was captured,
* and that the timestamp of the previous trace should be reused.
*/
#define U_TRACE_NO_TIMESTAMP ((uint64_t)0)
/**
* Driver provided callback to emit commands to capture a 64b timestamp
* into the specified timestamps buffer, at the specified index.
*
* The hw counter that the driver records should be something that runs at
* a fixed rate, even as the GPU freq changes. The same source used for
* GL_TIMESTAMP queries should be appropriate.
*/
typedef void (*u_trace_record_ts)(struct u_trace *ut,
struct pipe_resource *timestamps, unsigned idx);
/**
* Driver provided callback to read back a previously recorded timestamp.
* If necessary, this should block until the GPU has finished writing back
* the timestamps. (The timestamps will be read back in order, so it is
* safe to only synchronize on idx==0.)
*
* The returned timestamp should be in units of nanoseconds. The same
* timebase as GL_TIMESTAMP queries should be used.
*
* The driver can return the special U_TRACE_NO_TIMESTAMP value to indicate
* that no timestamp was captured and the timestamp from the previous trace
* will be re-used. (The first trace in the u_trace buf may not do this.)
* This allows the driver to detect cases where multiple tracepoints are
* emitted with no other intervening cmdstream, to avoid pointlessly
* capturing the same timestamp multiple times in a row.
*/
typedef uint64_t (*u_trace_read_ts)(struct u_trace_context *utctx,
struct pipe_resource *timestamps, unsigned idx);
/**
* The trace context provides tracking for "in-flight" traces, once the
* cmdstream that records timestamps has been flushed.
*/
struct u_trace_context {
struct pipe_context *pctx;
u_trace_record_ts record_timestamp;
u_trace_read_ts read_timestamp;
FILE *out;
/* Once u_trace_flush() is called u_trace_chunk's are queued up to
* render tracepoints on a queue. The per-chunk queue jobs block until
* timestamps are available.
*/
struct util_queue queue;
/* State to accumulate time across N chunks associated with a single
* batch (u_trace).
*/
uint64_t last_time_ns;
uint64_t first_time_ns;
uint32_t frame_nr;
/* list of unprocessed trace chunks in fifo order: */
struct list_head flushed_trace_chunks;
};
/**
* The u_trace ptr is passed as the first arg to generated tracepoints.
* It provides buffering for tracepoint payload until the corresponding
* driver cmdstream containing the emitted commands to capture is
* flushed.
*
* Individual tracepoints emitted to u_trace are expected to be "executed"
* (ie. timestamp captured) in FIFO order with respect to other tracepoints
* emitted to the same u_trace. But the order WRT other u_trace instances
* is undefined util u_trace_flush().
*/
struct u_trace {
struct u_trace_context *utctx;
struct list_head trace_chunks; /* list of unflushed trace chunks in fifo order */
bool enabled;
};
void u_trace_context_init(struct u_trace_context *utctx,
struct pipe_context *pctx,
u_trace_record_ts record_timestamp,
u_trace_read_ts read_timestamp);
void u_trace_context_fini(struct u_trace_context *utctx);
/**
* Flush (trigger processing) of traces previously flushed to the trace-context
* by u_trace_flush().
*
* This should typically be called in the driver's pctx->flush().
*/
void u_trace_context_process(struct u_trace_context *utctx, bool eof);
void u_trace_init(struct u_trace *ut, struct u_trace_context *utctx);
void u_trace_fini(struct u_trace *ut);
/**
* Flush traces to the parent trace-context. At this point, the expectation
* is that all the tracepoints are "executed" by the GPU following any previously
* flushed u_trace batch.
*
* This should typically be called when the corresponding cmdstream (containing
* the timestamp reads) is flushed to the kernel.
*/
void u_trace_flush(struct u_trace *ut);
/*
* TODO in some cases it is useful to have composite tracepoints like this,
* to log more complex data structures.. but this is probably not where they
* should live:
*/
void __trace_surface(struct u_trace *ut, const struct pipe_surface *psurf);
void __trace_framebuffer(struct u_trace *ut, const struct pipe_framebuffer_state *pfb);
static inline void
trace_framebuffer_state(struct u_trace *ut, const struct pipe_framebuffer_state *pfb)
{
if (likely(!ut->enabled))
return;
__trace_framebuffer(ut, pfb);
for (unsigned i = 0; i < pfb->nr_cbufs; i++) {
if (pfb->cbufs[i]) {
__trace_surface(ut, pfb->cbufs[i]);
}
}
if (pfb->zsbuf) {
__trace_surface(ut, pfb->zsbuf);
}
}
#endif /* _U_TRACE_H */
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