Commit-ID: a7fa19f5a255cc8970202d5c54092089a01fc042 Gitweb: https://git.kernel.org/tip/a7fa19f5a255cc8970202d5c54092089a01fc042 Author: Adrian Hunter <adrian.hun...@intel.com> AuthorDate: Tue, 4 Jun 2019 16:00:06 +0300 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Mon, 10 Jun 2019 16:20:12 -0300
perf intel-pt: Add intel_pt_fast_forward() Intel PT decoding is done in time order. In order to support efficient time interval filtering, add a facility to "fast forward" towards a particular timestamp. That involves finding the right buffer, stepping to that buffer, and then stepping forward PSBs. Because decoding must begin at a PSB, "fast forward" stops at the last PSB that has a timestamp before the target timestamp. Signed-off-by: Adrian Hunter <adrian.hun...@intel.com> Cc: Jin Yao <yao....@linux.intel.com> Cc: Jiri Olsa <jo...@redhat.com> Link: http://lkml.kernel.org/r/20190604130017.31207-9-adrian.hun...@intel.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- .../perf/util/intel-pt-decoder/intel-pt-decoder.c | 130 +++++++++++++++++++++ .../perf/util/intel-pt-decoder/intel-pt-decoder.h | 2 + 2 files changed, 132 insertions(+) diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c index dde6a7a97a7a..c374a856e73f 100644 --- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c @@ -126,6 +126,7 @@ struct intel_pt_decoder { uint64_t timestamp; uint64_t tsc_timestamp; uint64_t ref_timestamp; + uint64_t buf_timestamp; uint64_t sample_timestamp; uint64_t ret_addr; uint64_t ctc_timestamp; @@ -519,6 +520,7 @@ static int intel_pt_get_data(struct intel_pt_decoder *decoder, bool reposition) intel_pt_log("No more data\n"); return -ENODATA; } + decoder->buf_timestamp = buffer.ref_timestamp; if (!buffer.consecutive || reposition) { intel_pt_reposition(decoder); decoder->ref_timestamp = buffer.ref_timestamp; @@ -2854,3 +2856,131 @@ unsigned char *intel_pt_find_overlap(unsigned char *buf_a, size_t len_a, return buf_b; /* No overlap */ } } + +/** + * struct fast_forward_data - data used by intel_pt_ff_cb(). + * @timestamp: timestamp to fast forward towards + * @buf_timestamp: buffer timestamp of last buffer with trace data earlier than + * the fast forward timestamp. + */ +struct fast_forward_data { + uint64_t timestamp; + uint64_t buf_timestamp; +}; + +/** + * intel_pt_ff_cb - fast forward lookahead callback. + * @buffer: Intel PT trace buffer + * @data: opaque pointer to fast forward data (struct fast_forward_data) + * + * Determine if @buffer trace is past the fast forward timestamp. + * + * Return: 1 (stop lookahead) if @buffer trace is past the fast forward + * timestamp, and 0 otherwise. + */ +static int intel_pt_ff_cb(struct intel_pt_buffer *buffer, void *data) +{ + struct fast_forward_data *d = data; + unsigned char *buf; + uint64_t tsc; + size_t rem; + size_t len; + + buf = (unsigned char *)buffer->buf; + len = buffer->len; + + if (!intel_pt_next_psb(&buf, &len) || + !intel_pt_next_tsc(buf, len, &tsc, &rem)) + return 0; + + tsc = intel_pt_8b_tsc(tsc, buffer->ref_timestamp); + + intel_pt_log("Buffer 1st timestamp " x64_fmt " ref timestamp " x64_fmt "\n", + tsc, buffer->ref_timestamp); + + /* + * If the buffer contains a timestamp earlier that the fast forward + * timestamp, then record it, else stop. + */ + if (tsc < d->timestamp) + d->buf_timestamp = buffer->ref_timestamp; + else + return 1; + + return 0; +} + +/** + * intel_pt_fast_forward - reposition decoder forwards. + * @decoder: Intel PT decoder + * @timestamp: timestamp to fast forward towards + * + * Reposition decoder at the last PSB with a timestamp earlier than @timestamp. + * + * Return: 0 on success or negative error code on failure. + */ +int intel_pt_fast_forward(struct intel_pt_decoder *decoder, uint64_t timestamp) +{ + struct fast_forward_data d = { .timestamp = timestamp }; + unsigned char *buf; + size_t len; + int err; + + intel_pt_log("Fast forward towards timestamp " x64_fmt "\n", timestamp); + + /* Find buffer timestamp of buffer to fast forward to */ + err = decoder->lookahead(decoder->data, intel_pt_ff_cb, &d); + if (err < 0) + return err; + + /* Walk to buffer with same buffer timestamp */ + if (d.buf_timestamp) { + do { + decoder->pos += decoder->len; + decoder->len = 0; + err = intel_pt_get_next_data(decoder, true); + /* -ENOLINK means non-consecutive trace */ + if (err && err != -ENOLINK) + return err; + } while (decoder->buf_timestamp != d.buf_timestamp); + } + + if (!decoder->buf) + return 0; + + buf = (unsigned char *)decoder->buf; + len = decoder->len; + + if (!intel_pt_next_psb(&buf, &len)) + return 0; + + /* + * Walk PSBs while the PSB timestamp is less than the fast forward + * timestamp. + */ + do { + uint64_t tsc; + size_t rem; + + if (!intel_pt_next_tsc(buf, len, &tsc, &rem)) + break; + tsc = intel_pt_8b_tsc(tsc, decoder->buf_timestamp); + /* + * A TSC packet can slip past MTC packets but, after fast + * forward, decoding starts at the TSC timestamp. That means + * the timestamps may not be exactly the same as the timestamps + * that would have been decoded without fast forward. + */ + if (tsc < timestamp) { + intel_pt_log("Fast forward to next PSB timestamp " x64_fmt "\n", tsc); + decoder->pos += decoder->len - len; + decoder->buf = buf; + decoder->len = len; + intel_pt_reposition(decoder); + } else { + break; + } + } while (intel_pt_step_psb(&buf, &len)); + + return 0; +} diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h index de36254c6ac9..e633fad2fd5d 100644 --- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h @@ -130,6 +130,8 @@ void intel_pt_decoder_free(struct intel_pt_decoder *decoder); const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder); +int intel_pt_fast_forward(struct intel_pt_decoder *decoder, uint64_t timestamp); + unsigned char *intel_pt_find_overlap(unsigned char *buf_a, size_t len_a, unsigned char *buf_b, size_t len_b, bool have_tsc, bool *consecutive);
