This patch further improves math function benchmarking by adding a latency
test in addition to throughput. This enables more accurate comparisons of the
math functions. The latency test works by creating a dependency on the previous
iteration: func_res = F (func_res * zero + input[i]). The multiply by zero
avoids changing the input.
It reports reciprocal throughput and latency in nanoseconds (depending on the
timing header used) and max/min throughput in iterations per second:
"workload-spec2006.wrf": {
"reciprocal-throughput": 100,
"latency": 200,
"max-throughput": 1.0e+07,
"min-throughput": 5.0e+06
}
* benchtests/bench-skeleton.c (main): Add support for
latency benchmarking.
* benchtests/scripts/bench.py: Add support for latency benchmarking.
Make the memmove benchmarks (bench-memmove and bench-memmove-large)
print their output in JSON so that they can be evaluated using the
compare_strings.py script.
* benchtests/bench-memmove-large.c: Print output in JSON
format.
* benchtests/bench-memmove.c: Likewise.
The test run is unnecessary and interferes with the benchmark. The
tests are done during make check, so they're unnecessary here.
* benchtests/bench-memccpy.c (do_one_test): Remove checks.
* benchtests/bench-memchr.c (do_one_test): Likewise.
* benchtests/bench-memcpy-large.c (do_one_test): Likewise.
* benchtests/bench-memcpy.c (do_one_test): Likewise.
* benchtests/bench-memmove-large.c (do_one_test): Likewise.
* benchtests/bench-memmove.c (do_one_test): Likewise.
* benchtests/bench-memset-large.c (do_one_test): Likewise.
* benchtests/bench-memset.c (do_one_test): Likewise.
* benchtests/bench-string.h (test_init): Remove memsets.
The compare_strings.py script generates a graph for the benchmarks it
performs a comparison on and that fails if X is not available. Avoid
the error and ensure that only the graph is generated and saved as a
PNG file.
* benchtests/scripts/compare_strings.py: Avoid display error
when generating graph.
This patch allows one to provide the function name using an optional
-base option to compare all other functions against. This is useful
when pitching one implementation of a string function against
alternatives. In the absence of this option, comparisons are done
against the first ifunc in the list.
* benchtests/scripts/compare_strings.py (main): Add an
optional -base option.
(process_results): New argument base_func.
The hardcoded 'memcpy' name turns up in other derived tests like
mempcpy.
* benchtests/bench-memcpy.c (test_main): Use TEST_NAME instead of
hardcoding memcpy.
* benchtests/bench-memcpy-large.c (test_name): Likewise.
* benchtests/bench-memcpy-random.c (test_name): Likewise.
Read the memcpy results in json and print out the results in tabular
form, in addition to generating a graph of the results to compare all
of the implementations.
The format of the output is extensible enough to allow this kind of
analysis to be done on other string functions as well.
* benchtests/scripts/benchout_strings.schema.json: New file.
* benchtests/scripts/compare_strings.py: New file.
Print the benchmark output for various memcpy benchmarks in json so
that it can be predictably parsed and analyzed.
* benchtests/bench-memcpy-large.c: Include json-lib.h.
(do_one_test): Print json.
(do_test): Likewise.
(test_main): Likewise.
* benchtests/bench-memcpy-random.c: Include json-lib.h.
(do_one_test): Print json.
(do_test): Likewise.
(test_main): Likewise.
* benchtests/bench-memcpy.c: Include json-lib.h.
(do_one_test): Print json.
(do_test): Likewise.
(test_main): Likewise.
Enhance the json module in benchtests to print signed and unsigned
integers and string array elements.
* benchtests/json-lib.h: Include inttypes.h.
(json_attr_int, json_attr_int, json_element_string,
json_element_int, json_element_uint): New functions.
* benchtests/json-lib.c: (json_attr_int, json_attr_int,
json_element_string, json_element_int, json_element_uint): New
functions.
Add a workload for powf. This is a reduced trace based on 2.3 billion
samples extracted from wrf. The distribution of values, in particular
frequency of commonly used operands is the same as in the full trace.
* benchtests/powf-inputs: Add reduced trace from wrf.
Improve support for math function benchmarking. This patch adds
a feature that allows accurate benchmarking of traces extracted
from real workloads. This is done by iterating over all samples
rather than repeating each sample many times (which completely
ignores branch prediction and cache effects). A trace can be
added to existing math function inputs via
"## name: workload-<name>", followed by the trace.
* benchtests/README: Describe workload feature.
* benchtests/bench-skeleton.c (main): Add support for
benchmarking traces from workloads.
Add powf() bench test with input which covers these cases:
- positive base to positive exponent
- exponent 0
- negative base to even exponent
- exponent 1
- exponent -1
- squared
- squareroot
- 1 to negative exponent
- -1 to negative exponent
- base 0
- -1 to even exponent
- small base
- small exponent
* benchtests/Makefile (bench-math): Add powf.
* benchtests/powf-inputs: New file.
Current allocate_stack logic for create stacks is to first mmap all
the required memory with the desirable memory and then mprotect the
guard area with PROT_NONE if required. Although it works as expected,
it pessimizes the allocation because it requires the kernel to actually
increase commit charge (it counts against the available physical/swap
memory available for the system).
The only issue is to actually check this change since side-effects are
really Linux specific and to actually account them it would require a
kernel specific tests to parse the system wide information. On the kernel
I checked /proc/self/statm does not show any meaningful difference for
vmm and/or rss before and after thread creation. I could only see
really meaningful information checking on system wide /proc/meminfo
between thread creation: MemFree, MemAvailable, and Committed_AS shows
large difference without the patch. I think trying to use these
kind of information on a testcase is fragile.
The BZ#18988 reports shows that the commit pages are easily seen with
mlockall (MCL_FUTURE) (with lock all pages that become mapped in the
process) however a more straighfoward testcase shows that pthread_create
could be faster using this patch:
--
static const int inner_count = 256;
static const int outer_count = 128;
static
void *thread1(void *arg)
{
return NULL;
}
static
void *sleeper(void *arg)
{
pthread_t ts[inner_count];
for (int i = 0; i < inner_count; i++)
pthread_create (&ts[i], &a, thread1, NULL);
for (int i = 0; i < inner_count; i++)
pthread_join (ts[i], NULL);
return NULL;
}
int main(void)
{
pthread_attr_init(&a);
pthread_attr_setguardsize(&a, 1<<20);
pthread_attr_setstacksize(&a, 1134592);
pthread_t ts[outer_count];
for (int i = 0; i < outer_count; i++)
pthread_create(&ts[i], &a, sleeper, NULL);
for (int i = 0; i < outer_count; i++)
pthread_join(ts[i], NULL);
assert(r == 0);
}
return 0;
}
--
On x86_64 (4.4.0-45-generic, gcc 5.4.0) running the small benchtests
I see:
$ time ./test
real 0m3.647s
user 0m0.080s
sys 0m11.836s
While with the patch I see:
$ time ./test
real 0m0.696s
user 0m0.040s
sys 0m1.152s
So I added a pthread_create benchtest (thread_create) which check
the thread creation latency. As for the simple benchtests, I saw
improvements in thread creation on all architectures I tested the
change.
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
arm-linux-gnueabihf, powerpc64le-linux-gnu, sparc64-linux-gnu,
and sparcv9-linux-gnu.
[BZ #18988]
* benchtests/thread_create-inputs: New file.
* benchtests/thread_create-source.c: Likewise.
* support/xpthread_attr_setguardsize.c: Likewise.
* support/Makefile (libsupport-routines): Add
xpthread_attr_setguardsize object.
* support/xthread.h: Add xpthread_attr_setguardsize prototype.
* benchtests/Makefile (bench-pthread): Add thread_create.
* nptl/allocatestack.c (allocate_stack): Call mmap with PROT_NONE and
then mprotect the required area.
bench-memchr.c is shared with bench-memrchr.c. This patch adds some
tests for positions close to the beginning for memrchr, which are
equivalent to positions close to the end for memchr.
* benchtests/bench-memchr.c (do_test): Print out both length
and position.
(test_main): Also test the position close to the beginning for
memrchr.
cppflags-iterator.mk no longer has anything to do with CPPFLAGS; all
it does is set libof-$(foo) for a list of files. extra-modules.mk
does the same thing, but with a different input variable, and doesn't
let the caller control the module. Therefore, this patch gives
cppflags-iterator.mk a better name, removes extra-modules.mk, and
updates all uses of both.
* extra-modules.mk: Delete file.
* cppflags-iterator.mk: Rename to ...
* libof-iterator.mk: ...this. Adjust comments.
* Makerules, extra-lib.mk, benchtests/Makefile, elf/Makefile
* elf/rtld-Rules, iconv/Makefile, locale/Makefile, malloc/Makefile
* nscd/Makefile, sunrpc/Makefile, sysdeps/s390/Makefile:
Use libof-iterator.mk instead of cppflags-iterator.mk or
extra-modules.mk.
* benchtests/strcoll-inputs/filelist#en_US.UTF-8: Remove
extra-modules.mk and cppflags-iterator.mk, add libof-iterator.mk.
of the size and alignment is based on a trace of SPEC2006. Instead of
repeating the same copy over and over again like the existing tests, it times
several thousand different copies to more accurately estimate the overhead of
branch prediction.
* benchtests/Makefile (string-benchset): Add memcpy-random.
* benchtests/bench-memcpy-random.c: New file.
Add a configure check that looks for python3 and python in that order
since we had agreed in the past to prefer python3 over python in all
our code. The patch also adjusts invocations through the various
Makefiles to use the set variable.
* configure.ac: Check for python3 or python.
* configure: Regenerated.
* config.make.in (PYTHON): New variable.
* benchtests/Makefile: Don't define PYTHON.
(bench): Define target only if PYTHON was defined.
* Rules: Don't define PYTHON.
Define pretty printer targets only if PYTHON was defined.
(tests-printers): Add to tests-unsupported if PYTHON is not
found.
(python-flags, python-invoke): Remove.
(tests-printers-out): Use PYTHON instead of python-invoke.
Currently strsep calls strpbrk is is now a veneer to strcspn. Calling
strcspn directly is faster. Since it handles a delimiter string of size
1 as a special case, this is not needed in strsep itself. Although this
means there is a slightly higher overhead if the delimiter size is 1,
all other cases are slightly faster. The overall performance gain is 5-10%
on AArch64.
The string/bits/string2.h header contains optimizations for constant
delimiters of size 1-3. Benchmarking these showed similar performance for
size 1 (since in all cases strchr/strchrnul is used), while size 2 and 3
can give up to 2x speedup for small input strings. However if these cases
are common it seems much better to add this optimization to strcspn.
So move these header optimizations to string-inlines.c.
Improve the strsep benchmark so that it actually benchmarks something.
The current version contains a delimiter character at every position in the
input string, so there is very little work to do, and the extremely inefficent
simple_strsep implementation appears fastest in every case. The new version
has either no match in the input for the fail case and a match halfway in the
input for the success case. The input is then restored so that each iteration
does exactly the same amount of work. Reduce the number of testcases since
simple_strsep takes a lot of time now.
* benchtests/bench-strsep.c (oldstrsep): Add old implementation.
(do_one_test) Restore original string so iteration works.
* string/string-inlines.c (do_test): Create better input strings.
(test_main) Reduce number of testruns.
* string/string-inlines.c (__old_strsep_1c): New function.
(__old_strsep_2c): Likewise.
(__old_strsep_3c): Likewise.
* string/strsep.c (__strsep): Remove case of small delim string.
Call strcspn directly rather than strpbrk.
* string/bits/string2.h (__strsep): Remove define.
(__strsep_1c): Remove.
(__strsep_2c): Remove.
(__strsep_3c): Remove.
(strsep): Remove.
* sysdeps/unix/sysv/linux/internal_statvfs.c
(__statvfs_getflags): Rename to __strsep.
This patch adds fmaxf and fminf benchtests. It is based on
math/s_fmax_template.c implementation which checks for basically four
different classes:
1. if x is greater or equal than y.
2. if x is less than y.
3. if x or y is signaling.
4. if y is nan.
Cases 1 and 2 are used for default input number (by mixing normal double
numbers and infinity), while case 3 and 4 are used each for on for a
benchmark class.
Checked on x86_64-linux-gnu and powerpc64-linux-gnu.
* benchtests/Makefile (bench-math): Add fminf and fmaxf.
(CFLAGS-bench-fmaxf.c): New rule.
(CFLAGS-bench-fminf.c): Likewise.
* benchtests/fmaxf-inputs: New file.
* benchtests/fminf-inputs: Likewise.
This patch adds fmax and fmin benchtests. It is based math/s_fmax_template.c
implementation which checks for basically four different classes:
1. if x is greater or equal than y.
2. if x is less than y.
3. if x or y is signaling.
4. if y is nan.
Cases 1 and 2 are used for default input number (by mixing normal double
numbers and infinity), while case 3 and 4 are used each for on for a
benchmark class.
Checked on x86_64-linux-gnu and powerpc64-linux-gnu.
* benchtests/Makefile (bench-math): Add fmin and fmax.
(CFLAGS-bench-fmax.c): New rule.
(CFLAGS-bench-fmin.c): New rule.
* benchtests/fmax-inputs: New file.
* benchtests/fmin-inputs: Likewise.
Benchsets in benchtests use test-skeleton, so they too need to be
linked against the new libsupport DSO.
* benchtests/Makefile (binaries-benchset): Depend on libsupport
DSO.
calls strcspn, call strcspn directly so we get the end of the token without
an extra call to rawmemchr. Also avoid an unnecessary call to strcspn after
the last token by adding an early exit for an empty string. Change strtok
to tailcall strtok_r to avoid unnecessary code duplication.
Remove the special header optimization for strtok_r of a 1-character
constant string - both strspn and strcspn contain optimizations for this
case. Benchmarking this showed similar performance in the worst case,
but up to 5.5x better performance in the "found" case for large inputs.
* benchtests/bench-strtok.c (oldstrtok): Add old implementation.
* string/strtok.c (strtok): Change to tailcall __strtok_r.
* string/strtok_r.c (__strtok_r): Optimize for performance.
* string/string-inlines.c (__old_strtok_r_1c): New function.
* string/bits/string2.h (__strtok_r): Move to string-inlines.c.
This patch makes the sqrt benchmark use -fno-builtin, as already done
for benchmarks of ffs and ffsll, so that it actually benchmarks the
glibc function as (presumably) intended even in the presence of the
compiler inlining sqrt.
Tested for x86_64 and also used for benchmarking my ARM sqrt patch.
* benchtests/Makefile (CFLAGS-bench-sqrt.c): New variable.
Clear the destination buffer updated by the previous run in bench-memcpy.c
and test-memcpy.c to catch the error when the following implementations do
not copy anything.
[BZ #19907]
* benchtests/bench-memcpy.c (do_one_test): Clear the destination
buffer updated by the previous run.
* string/test-memcpy.c (do_one_test): Likewise.
* benchtests/bench-memmove.c (do_one_test): Add a comment.
* string/test-memmove.c (do_one_test): Likewise.
This patch adds full support for cross-building benchmarks. Some
benchmarks like those that need locales to be generated cannot be
built and are hence skipped for cross builds.
Tested by cross building for aarch64 on x86_64 and then running the
generated benchmark on aarch64.
* benchtests/Makefile (wcsmbs-benchset): Include only for
native builds and runs.
(LOCALES): Likewise.
(bench-build): Build timing-type here instead of the bench
target. Generate locale only for native builds.
* benchtests/README: Add note for cross-building.
For situations where we are cross-building or where we want to avoid
building on the target system, we want a way to only build benchmarks
and then copy them over to the target system to run them. I have also
added a simple enhancement for the 'bench' target where all benchmark
binaries are built and then the benchmarks executed.
Tested on arm.
Makefile.in (bench-build): New target.
Rules (PHONY): Add bench-build target.
benchtests/Makefile (bench): Depend on bench-build.
(bench-build): New target.
From the bug:
Obsolete locale. The ISO-639 code for Hebrew was changed from 'iw'
to 'he' in 1989, according to Bruno Haible on libc-alpha 2003-09-01.
Reported-by: Chris Leonard <cjlhomeaddress@gmail.com>
benchtests should use $(test-via-rtld-prefix) and $(+link-tests) like
other glibc tests.
[BZ #19783]
* benchtests/Makefile (run-bench): Replace $(rtld-prefix) with
$(test-via-rtld-prefix).
($(binaries-bench)): Replace $(+link) with $(+link-tests).
The ffs and ffsll functions were listed as math functions when they
are actually defined in strings.h and string.h respectively. Shuffle
around the Makefile variables a bit and make a separate space for ffs
and ffsll.
The sincos benchmark has only about a dozen inputs that don't measure
the impact of changes to various passes. Since much of the code
properties are inherited from sin and cos, copy those inputs in to get
more comprehensive coverage.
Prevent function calls that don't return anything from being optimized
out by the compiler by marking its input variables as used.
This prevents the sincos function call from being optimized out in the
benchmark.
ChangeLog:
2015-09-18 Wilco Dijkstra <wdijkstr@arm.com>
* benchtests/Makefile: Add bench-math-inlines, link with libm.
* benchtests/bench-math-inlines.c: New benchmark.
* benchtests/bench-util.h: New file.
* benchtests/bench-util.c: New file.
* benchtests/bench-skeleton.c: Add include of bench-util.c/h.
