linux-toradex.git/tools/lib/api, branch v6.11-rc3

tools api io: Move filling the io buffer to its own function

2024-05-30T17:05:34+00:00

In general a read fills 4kb so filling the buffer is a 1 in 4096
operation, move it out of the io__get_char function to avoid some
checking overhead and to better hint the function is good to inline.

For perf's IO intensive internal (non-rigorous) benchmarks there's a
small improvement to kallsyms-parsing with a default build.

Before:
```
$ perf bench internals all
Computing performance of single threaded perf event synthesis by
synthesizing events on the perf process itself:
  Average synthesis took: 146.322 usec (+- 0.305 usec)
  Average num. events: 61.000 (+- 0.000)
  Average time per event 2.399 usec
  Average data synthesis took: 145.056 usec (+- 0.155 usec)
  Average num. events: 329.000 (+- 0.000)
  Average time per event 0.441 usec

  Average kallsyms__parse took: 162.313 ms (+- 0.599 ms)
...
Computing performance of sysfs PMU event scan for 100 times
  Average core PMU scanning took: 53.720 usec (+- 7.823 usec)
  Average PMU scanning took: 375.145 usec (+- 23.974 usec)
```
After:
```
$ perf bench internals all
Computing performance of single threaded perf event synthesis by
synthesizing events on the perf process itself:
  Average synthesis took: 127.829 usec (+- 0.079 usec)
  Average num. events: 61.000 (+- 0.000)
  Average time per event 2.096 usec
  Average data synthesis took: 133.652 usec (+- 0.101 usec)
  Average num. events: 327.000 (+- 0.000)
  Average time per event 0.409 usec

  Average kallsyms__parse took: 150.415 ms (+- 0.313 ms)
...
Computing performance of sysfs PMU event scan for 100 times
  Average core PMU scanning took: 47.790 usec (+- 1.178 usec)
  Average PMU scanning took: 376.945 usec (+- 23.683 usec)
```

Signed-off-by: Ian Rogers 
Signed-off-by: Namhyung Kim 
Link: https://lore.kernel.org/r/20240519181716.4088459-1-irogers@google.com

tools api fs: Avoid reading whole file for a 1 byte bool

2023-11-30T22:25:19+00:00

sysfs__read_bool() used the first byte from a fully read file into a
string. It then looked at the first byte's value. Avoid doing this and
just read the first byte.

Signed-off-by: Ian Rogers 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Athira Jajeev 
Cc: Changbin Du 
Cc: Colin Ian King 
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: German Gomez 
Cc: Guilherme Amadio 
Cc: Huacai Chen 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: K Prateek Nayak 
Cc: Kajol Jain 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Li Dong 
Cc: Liam Howlett 
Cc: Mark Rutland 
Cc: Masami Hiramatsu (Google) 
Cc: Miguel Ojeda 
Cc: Ming Wang 
Cc: Nick Terrell 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Sandipan Das 
Cc: Sean Christopherson 
Cc: Steinar H. Gunderson 
Cc: Vincent Whitchurch 
Cc: Wenyu Liu 
Cc: Yang Jihong 
Link: https://lore.kernel.org/r/20231127220902.1315692-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

tools api fs: Switch filename__read_str to use io.h

2023-11-30T22:25:19+00:00

filename__read_str() has its own string reading code that allocates
memory before reading into it. The memory allocated is sized at BUFSIZ
that is 8kb. Most strings are short and so most of this 8kb is wasted.

Refactor io__getline(), as io__getdelim(), so that the newline character
can be configurable and ignored in the case of filename__read_str().

Code like build_caches_for_cpu() in perf's header.c will read many strings
and hold them in a data structure, in this case multiple strings per
cache level per CPU.

Using io.h's io__getline() avoids the wasted memory as strings are
temporarily read into a buffer on the stack before being copied to a
buffer that grows 128 bytes at a time and is never sized larger than the
string.

For a 16 hyperthread system the memory consumption of "perf record
true" is reduced by 180kb, primarily through saving memory when
reading the cache information.

Signed-off-by: Ian Rogers 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Athira Jajeev 
Cc: Changbin Du 
Cc: Colin Ian King 
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: German Gomez 
Cc: Guilherme Amadio 
Cc: Huacai Chen 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: K Prateek Nayak 
Cc: Kajol Jain 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Li Dong 
Cc: Liam Howlett 
Cc: Mark Rutland 
Cc: Masami Hiramatsu (Google) 
Cc: Miguel Ojeda 
Cc: Ming Wang 
Cc: Nick Terrell 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Sandipan Das 
Cc: Sean Christopherson 
Cc: Steinar H. Gunderson 
Cc: Vincent Whitchurch 
Cc: Wenyu Liu 
Cc: Yang Jihong 
Link: https://lore.kernel.org/r/20231127220902.1315692-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

libapi: Add missing linux/types.h header to get the __u64 type on io.h

2023-11-30T22:24:59+00:00

There are functions using __u64, so we need to have the linux/types.h
header otherwise we'll break when its not included before api/io.h.

Fixes: e95770af4c4a280f ("tools api: Add a lightweight buffered reading api")
Reviewed-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lore.kernel.org/lkml/ZWjDPL+IzPPsuC3X@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools api: Avoid potential double free

2023-10-12T17:01:57+00:00

io__getline will free the line on error but it doesn't clear the out
argument. This may lead to the line being freed twice, like in
tools/perf/util/srcline.c as detected by clang-tidy.

Signed-off-by: Ian Rogers 
Acked-by: Namhyung Kim 
Cc: Ravi Bangoria 
Cc: Nick Desaulniers 
Cc: Yang Jihong 
Cc: Huacai Chen 
Cc: Nathan Chancellor 
Cc: Kan Liang 
Cc: llvm@lists.linux.dev
Cc: Ming Wang 
Cc: Tom Rix 
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20231009183920.200859-17-irogers@google.com
Signed-off-by: Namhyung Kim

tools api: Add simple timeout to io read

2023-06-14T21:19:06+00:00

In situations like reading from a pipe it can be useful to have a
timeout so that the caller doesn't block indefinitely. Implement a
simple one based on poll.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Yang Jihong 
Link: http://lore.kernel.org/lkml/20230608061812.3715566-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

tools api fs: More thread safety for global filesystem variables

2023-06-14T02:40:32+00:00

Multiple threads, such as with "perf top", may race to initialize a
file system path like hugetlbfs. The racy initialization of the path
leads to at least memory leaks. To avoid this initialize each fs for
reading the mount point path with pthread_once.

Mounting the file system may also be racy, so introduce a mutex over
the function. This does mean that the path is being accessed with and
without a mutex, which is inherently racy but hopefully benign,
especially as there are fewer callers to fs__mount.

Remove the fs__entries by directly using global variables, this was
done as no argument like the index can be passed to the init once
routine.

Issue found and tested with "perf top" and address sanitizer.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230609224004.180988-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

tools api fs: Dynamically allocate cgroupfs mount point cache, removing 4128 bytes from .bss

2023-05-28T13:25:25+00:00

Move the cgroupfs_cache_entry 4128 byte array out of .bss.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: K Prateek Nayak 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Ross Zwisler 
Cc: Sean Christopherson 
Cc: Steven Rostedt (VMware) 
Cc: Tiezhu Yang 
Cc: Yang Jihong 
Link: https://lore.kernel.org/r/20230526183401.2326121-15-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

tools lib api fs tracing_path: Remove two unused MAX_PATH paths

2023-05-28T13:23:00+00:00

tracing_mnt was set but never written. tracing_events_path was set and
read on errors paths, but its value is exactly tracing_path with a
"/events" appended, so we can derive the value in the error
paths. There appears to have been a missing "/" when
tracing_events_path was initialized.

Signed-off-by: Ian Rogers 
Link: https://lore.kernel.org/r/20230526183401.2326121-8-irogers@google.com
Cc: K Prateek Nayak 
Cc: Ravi Bangoria 
Cc: Mark Rutland 
Cc: Ross Zwisler 
Cc: Steven Rostedt (Google) 
Cc: Sean Christopherson 
Cc: Yang Jihong 
Cc: Peter Zijlstra 
Cc: Adrian Hunter 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu (Google) 
Cc: Namhyung Kim 
Cc: Leo Yan 
Cc: Andi Kleen 
Cc: Alexander Shishkin 
Cc: Kan Liang 
Cc: Tiezhu Yang 
Cc: Ingo Molnar 
Cc: Paolo Bonzini 
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools api fs: Avoid large static PATH_MAX arrays

2023-05-28T13:22:40+00:00

Change struct fs to have a pointer to a dynamically allocated array
rather than an array. This reduces the size of fs__entries from 24,768
bytes to 240 bytes. Read paths into a stack allocated array and
strdup. Fix off-by-1 fscanf %s in fs__read_mounts caught by
address sanitizer.

Signed-off-by: Ian Rogers 
Link: https://lore.kernel.org/r/20230526183401.2326121-7-irogers@google.com
Cc: K Prateek Nayak 
Cc: Ravi Bangoria 
Cc: Mark Rutland 
Cc: Ross Zwisler 
Cc: Steven Rostedt (Google) 
Cc: Sean Christopherson 
Cc: Yang Jihong 
Cc: Peter Zijlstra 
Cc: Adrian Hunter 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu (Google) 
Cc: Namhyung Kim 
Cc: Leo Yan 
Cc: Andi Kleen 
Cc: Alexander Shishkin 
Cc: Kan Liang 
Cc: Tiezhu Yang 
Cc: Ingo Molnar 
Cc: Paolo Bonzini 
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo