Currently running the xray tools generates a number of errors:
$ ./bin/llvm-xray
: for the -k option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -d option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -o option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -f option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -s option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -r option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -p option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the -m option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
<snip>
Patch by Ryan Mansfield.
Differential Revision: https://reviews.llvm.org/D69386
Summary:
This reverts D50129 / rL338834: [XRay][tools] Use Support/JSON.h in llvm-xray convert
Abstractions are great.
Readable code is great.
JSON support library is a *good* idea.
However unfortunately, there is an internal detail that one needs
to be aware of in `llvm::json::Object` - it uses `llvm::DenseMap`.
So for **every** `llvm::json::Object`, even if you only store a single `int`
entry there, you pay the whole price of `llvm::DenseMap`.
Unfortunately, it matters for `llvm-xray`.
I was trying to analyse the `llvm-exegesis` analysis mode performance,
and for that i wanted to view the LLVM X-Ray log visualization in Chrome
trace viewer. And the `llvm-xray convert` is sluggish, and sometimes
even ended up being killed by OOM.
`xray-log.llvm-exegesis.lwZ0sT` was acquired from `llvm-exegesis`
(compiled with ` -fxray-instruction-threshold=128`)
analysis mode over `-benchmarks-file` with 10099 points (one full
latency measurement set), with normal runtime of 0.387s.
Timings:
Old: (copied from D58580)
```
$ perf stat -r 5 ./bin/llvm-xray convert -sort -symbolize -instr_map=./bin/llvm-exegesis -output-format=trace_event -output=/tmp/trace.yml xray-log.llvm-exegesis.lwZ0sT
Performance counter stats for './bin/llvm-xray convert -sort -symbolize -instr_map=./bin/llvm-exegesis -output-format=trace_event -output=/tmp/trace.yml xray-log.llvm-exegesis.lwZ0sT' (5 runs):
21346.24 msec task-clock # 1.000 CPUs utilized ( +- 0.28% )
314 context-switches # 14.701 M/sec ( +- 59.13% )
1 cpu-migrations # 0.037 M/sec ( +-100.00% )
2181354 page-faults # 102191.251 M/sec ( +- 0.02% )
85477442102 cycles # 4004415.019 GHz ( +- 0.28% ) (83.33%)
14526427066 stalled-cycles-frontend # 16.99% frontend cycles idle ( +- 0.70% ) (83.33%)
32371533721 stalled-cycles-backend # 37.87% backend cycles idle ( +- 0.27% ) (33.34%)
67896890228 instructions # 0.79 insn per cycle
# 0.48 stalled cycles per insn ( +- 0.03% ) (50.00%)
14592654840 branches # 683631198.653 M/sec ( +- 0.02% ) (66.67%)
212207534 branch-misses # 1.45% of all branches ( +- 0.94% ) (83.34%)
21.3502 +- 0.0585 seconds time elapsed ( +- 0.27% )
```
New:
```
$ perf stat -r 9 ./bin/llvm-xray convert -sort -symbolize -instr_map=./bin/llvm-exegesis -output-format=trace_event -output=/tmp/trace.yml xray-log.llvm-exegesis.lwZ0sT
Performance counter stats for './bin/llvm-xray convert -sort -symbolize -instr_map=./bin/llvm-exegesis -output-format=trace_event -output=/tmp/trace.yml xray-log.llvm-exegesis.lwZ0sT' (9 runs):
7178.38 msec task-clock # 1.000 CPUs utilized ( +- 0.26% )
182 context-switches # 25.402 M/sec ( +- 28.84% )
0 cpu-migrations # 0.046 M/sec ( +- 70.71% )
33701 page-faults # 4694.994 M/sec ( +- 0.88% )
28761053971 cycles # 4006833.933 GHz ( +- 0.26% ) (83.32%)
2028297997 stalled-cycles-frontend # 7.05% frontend cycles idle ( +- 1.61% ) (83.32%)
10773154901 stalled-cycles-backend # 37.46% backend cycles idle ( +- 0.38% ) (33.36%)
36199132874 instructions # 1.26 insn per cycle
# 0.30 stalled cycles per insn ( +- 0.03% ) (50.02%)
6434504227 branches # 896420204.421 M/sec ( +- 0.03% ) (66.68%)
73355176 branch-misses # 1.14% of all branches ( +- 1.46% ) (83.33%)
7.1807 +- 0.0190 seconds time elapsed ( +- 0.26% )
```
So using `llvm::json` nearly triples run-time on that test case.
(+3x is times, not percent.)
Memory:
Old:
```
total runtime: 39.88s.
bytes allocated in total (ignoring deallocations): 79.07GB (1.98GB/s)
calls to allocation functions: 33267816 (834135/s)
temporary memory allocations: 5832298 (146235/s)
peak heap memory consumption: 9.21GB
peak RSS (including heaptrack overhead): 147.98GB
total memory leaked: 1.09MB
```
New:
```
total runtime: 17.42s.
bytes allocated in total (ignoring deallocations): 5.12GB (293.86MB/s)
calls to allocation functions: 21382982 (1227284/s)
temporary memory allocations: 232858 (13364/s)
peak heap memory consumption: 350.69MB
peak RSS (including heaptrack overhead): 2.55GB
total memory leaked: 79.95KB
```
Diff:
```
total runtime: -22.46s.
bytes allocated in total (ignoring deallocations): -73.95GB (3.29GB/s)
calls to allocation functions: -11884834 (529155/s)
temporary memory allocations: -5599440 (249307/s)
peak heap memory consumption: -8.86GB
peak RSS (including heaptrack overhead): 0B
total memory leaked: -1.01MB
```
So using `llvm::json` increases *peak* memory consumption on *this* testcase ~+27x.
And total allocation count +15x. Both of these numbers are times, *not* percent.
And note that memory usage is clearly unbound with `llvm::json`, it directly depends
on the length of the log, so peak memory consumption is always increasing.
This isn't so with the dumb code, there is no accumulating memory consumption,
peak memory consumption is fixed. Naturally, that means it will handle *much*
larger logs without OOM'ing.
Readability is good, but the price is simply unacceptable here.
Too bad none of this analysis was done as part of the development/review D50129 itself.
Reviewers: dberris, kpw, sammccall
Reviewed By: dberris
Subscribers: riccibruno, hans, courbet, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58584
llvm-svn: 354764
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
This change cuts across LLVM and compiler-rt to add support for
rendering custom events in the XRayRecord type, to allow for including
user-provided annotations in the output YAML (as raw bytes).
This work enables us to add custom event and typed event records into
the `llvm::xray::Trace` type for user-provided events. This can then be
programmatically handled through the C++ API and can be included in some
of the tooling as well. For now we support printing the raw data we
encounter in the custom events in the converted output.
Future work will allow us to start interpreting these custom and typed
events through a yet-to-be-defined API for extending the trace analysis
library.
Reviewers: mboerger
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D54139
llvm-svn: 346214
Summary:
This change removes the ad-hoc implementation used by llvm-xray's
`convert` subcommand to generate JSON encoded catapult (AKA Chrome
Trace Viewer) trace output, to instead use the JSON encoder now in the
Support library.
Reviewers: kpw, zturner, eizan
Reviewed By: kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50129
llvm-svn: 338834
Summary:
llvm-xray changes:
- account-mode - process-id {...} shows after thread-id
- convert-mode - process {...} shows after thread
- parses FDR and basic mode pid entries
- Checks version number for FDR log parsing.
Basic logging changes:
- Update header version from 2 -> 3
FDR logging changes:
- Update header version from 2 -> 3
- in writeBufferPreamble, there is an additional PID Metadata record (after thread id record and tsc record)
Test cases changes:
- fdr-mode.cc, fdr-single-thread.cc, fdr-thread-order.cc modified to catch process id output in the log.
Reviewers: dberris
Reviewed By: dberris
Subscribers: hiraditya, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D49153
llvm-svn: 336974
Provide some free functions to reduce verbosity of endian-writing
a single value, and replace the endianness template parameter with
a field.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47032
llvm-svn: 332757
Summary:
This brings the filenames in accordance to the style guide and LLVM
conventions for C++ filenames.
As suggested by rnk@ in D46068.
Reviewers: rnk
Subscribers: mgorny, mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D46301
llvm-svn: 331321
