huntedbytheirsandSisyphus
53c8531eab
System-headers-only harness timing the five L1 string functions (strlen, strcmp, memcpy, memmove, memset) at 8- and 64-byte inputs. Calls go through volatile function pointers to defeat builtin substitution and LICM hoisting; correctness self-asserts route through the same pointers. Prints FUNC@SIZE ns/call lines. bench_string uses empty per-target CPPFLAGS (no -I include) so it links against whichever libc --with-libc= selects; the bench target runs it always and bench_vlibc only under BENCH_LINK_VLIBC. Both programs relink when config.status changes, so a reconfigure cannot silently reuse a binary from the previous libc. Measured vs glibc 2.44 (median of 3 runs): mem* 1.0-3.3x, strlen/strcmp 3.2-3.9x — word-at-a-time vs AVX2, all sane. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <[email protected]>
54 lines
1.8 KiB
Makefile
54 lines
1.8 KiB
Makefile
# vlibc — benchmark harnesses (musts/BENCHMARKING.md).
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AM_CPPFLAGS = -I$(top_srcdir)/include
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AM_CFLAGS = @VLIBC_CFLAGS@
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# Built only on demand (via `make bench`), so `make all` does not need the
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# library to be built first.
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EXTRA_PROGRAMS = bench_vlibc bench_string
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bench_vlibc_SOURCES = bench_vlibc.c
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bench_string_SOURCES = bench_string.c
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# bench_string is a system-headers-only translation unit (it times whichever
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# libc it is linked against), so it must NOT inherit AM_CPPFLAGS: -I include
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# would pull vlibc's self-contained <stddef.h>/<string.h> into the same TU as
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# the system <stdio.h>/<time.h> and double-define size_t/NULL/offsetof.
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# bench_vlibc keeps the inherited -I include.
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bench_string_CPPFLAGS =
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# By default benchmarks link against vlibc itself. --with-libc=glibc links the
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# same harness against the system glibc; --with-libc=musl builds it with
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# musl-gcc for the musl reference.
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if BENCH_LINK_VLIBC
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bench_vlibc_LDADD = ../libvlibc.la
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bench_string_LDADD = ../libvlibc.la
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else
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bench_vlibc_LDADD =
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bench_string_LDADD =
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endif
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if BENCH_LINK_MUSL
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CC = $(MUSL_CC)
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endif
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# Relink whenever the configuration changes (autogen.sh reruns configure and
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# rewrites config.status). --with-libc only affects the link (LDADD), and the
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# objects are compile-time identical, so make would otherwise reuse a stale
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# binary from the previous configuration and the wrong libc would be measured.
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EXTRA_bench_string_DEPENDENCIES = $(top_builddir)/config.status
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EXTRA_bench_vlibc_DEPENDENCIES = $(top_builddir)/config.status
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# bench_vlibc.c calls vlibc_version(), which exists only in vlibc — under
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# --with-libc=glibc/musl it cannot link, so it is built and run only in the
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# vlibc build. bench_string links either way and runs always.
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if BENCH_LINK_VLIBC
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bench: bench_vlibc bench_string
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./bench_vlibc
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./bench_string
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else
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bench: bench_string
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./bench_string
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endif
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.PHONY: bench
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