powerpc: add sysconf support for cache geometries
Commit Message
There is currently no "cross-platform" (x86 and POWER) support for
determining the cacheline size.
This patch adds support to sysconf() to correctly report cacheline sizes
based on the information in the auxilliary vector.
Thus, using sysconf() is a cross-platform (x86 and POWER) solution for
determining cacheline sizes.
Support is added (on powerpc) for:
_SC_LEVEL1_ICACHE_SIZE _SC_LEVEL1_ICACHE_ASSOC _SC_LEVEL1_ICACHE_LINESIZE
_SC_LEVEL1_DCACHE_SIZE _SC_LEVEL1_DCACHE_ASSOC _SC_LEVEL1_DCACHE_LINESIZE
_SC_LEVEL2_CACHE_SIZE _SC_LEVEL2_CACHE_ASSOC _SC_LEVEL2_CACHE_LINESIZE
_SC_LEVEL3_CACHE_SIZE _SC_LEVEL3_CACHE_ASSOC _SC_LEVEL3_CACHE_LINESIZE
2017-04-28 Paul A. Clarke <pc@us.ibm.com>
* sysdeps/unix/sysv/linux/powerpc/sysconf.c: New file.
Add powerpc-specific overrides for L1, L2, L3 CACHE_SIZEs,
CACHE_ASSOCs, and CACHE_LINESIZEs, retrieving from auxv.
* sysdeps/unix/sysv/linux/powerpc/tst-sysconf.c: New file.
Invoke newly supported sysconf values for powerpc, and report
results. If none are supported, report so.
* sysdeps/unix/sysv/linux/powerpc/Makefile (tests): Add new test,
tst-sysconf.
---
sysdeps/unix/sysv/linux/powerpc/Makefile | 1 +
sysdeps/unix/sysv/linux/powerpc/sysconf.c | 96 +++++++++++++++++++++++++++
sysdeps/unix/sysv/linux/powerpc/tst-sysconf.c | 75 +++++++++++++++++++++
3 files changed, 172 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/powerpc/sysconf.c
create mode 100644 sysdeps/unix/sysv/linux/powerpc/tst-sysconf.c
Comments
On Fri, 28 Apr 2017, Paul Clarke wrote:
> * sysdeps/unix/sysv/linux/powerpc/tst-sysconf.c: New file.
This suffers the usual problem of adding a sysdeps test with the same name
as a non-sysdeps test: it would override nptl/tst-sysconf.c and
posix/tst-sysconf.c on systems using this sysdeps directory.
Perhaps we should have a naming convention for sysdeps tests, that all
tests added in sysdeps directories (as opposed to files there that wrap
non-sysdeps test implementations) include something system-specific in
their names, so this might be test-powerpc-linux-sysconf.c and linux/
tests might be renamed to test-linux-*.c, to avoid accidental overriding.
> +#define TEST_FUNCTION do_test ()
> +#include "../test-skeleton.c"
New tests should be using <support/test-driver.c>. See:
https://sourceware.org/glibc/wiki/Testing/Testsuite#Writing_a_test_case
@@ -29,6 +29,7 @@ ifeq ($(subdir),misc)
sysdep_headers += bits/ppc.h
sysdep_routines += get_timebase_freq
tests += test-gettimebasefreq
+tests += tst-sysconf
endif
ifeq ($(subdir),nptl)
new file mode 100644
@@ -0,0 +1,96 @@
+/* Get system-specific information at run-time. Linux/powerpc version.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+
+static long linux_sysconf (int name);
+
+static long
+auxv2sysconf (unsigned long type)
+{
+ long rc;
+ rc = getauxval (type);
+ if (rc == 0)
+ {
+ __set_errno (EINVAL);
+ rc = -1;
+ }
+ return rc;
+}
+
+static long
+auxv2sysconf_cache_associativity (unsigned long type)
+{
+ long rc;
+ rc = auxv2sysconf (type);
+ if (rc != -1)
+ rc = (rc & 0xffff0000) >> 16;
+ return rc;
+}
+
+static long
+auxv2sysconf_cache_linesize (unsigned long type)
+{
+ long rc;
+ rc = auxv2sysconf (type);
+ if (rc != -1)
+ rc = rc & 0xffff;
+ return rc;
+}
+
+/* Get the value of the system variable NAME. */
+long int
+__sysconf (int name)
+{
+ switch (name)
+ {
+ case _SC_LEVEL1_ICACHE_SIZE:
+ return auxv2sysconf (AT_L1I_CACHESIZE);
+ case _SC_LEVEL1_ICACHE_ASSOC:
+ return auxv2sysconf_cache_associativity (AT_L1I_CACHEGEOMETRY);
+ case _SC_LEVEL1_ICACHE_LINESIZE:
+ return auxv2sysconf_cache_linesize (AT_L1I_CACHEGEOMETRY);
+ case _SC_LEVEL1_DCACHE_SIZE:
+ return auxv2sysconf (AT_L1D_CACHESIZE);
+ case _SC_LEVEL1_DCACHE_ASSOC:
+ return auxv2sysconf_cache_associativity (AT_L1D_CACHEGEOMETRY);
+ case _SC_LEVEL1_DCACHE_LINESIZE:
+ return auxv2sysconf_cache_linesize (AT_L1D_CACHEGEOMETRY);
+ case _SC_LEVEL2_CACHE_SIZE:
+ return auxv2sysconf (AT_L2_CACHESIZE);
+ case _SC_LEVEL2_CACHE_ASSOC:
+ return auxv2sysconf_cache_associativity (AT_L2_CACHEGEOMETRY);
+ case _SC_LEVEL2_CACHE_LINESIZE:
+ return auxv2sysconf_cache_linesize (AT_L2_CACHEGEOMETRY);
+ case _SC_LEVEL3_CACHE_SIZE:
+ return auxv2sysconf (AT_L3_CACHESIZE);
+ case _SC_LEVEL3_CACHE_ASSOC:
+ return auxv2sysconf_cache_associativity (AT_L3_CACHEGEOMETRY);
+ case _SC_LEVEL3_CACHE_LINESIZE:
+ return auxv2sysconf_cache_linesize (AT_L3_CACHEGEOMETRY);
+ default:
+ return linux_sysconf (name);
+ }
+}
+
+/* Now the generic Linux version. */
+#undef __sysconf
+#define __sysconf static linux_sysconf
+#include "../sysconf.c"
new file mode 100644
@@ -0,0 +1,75 @@
+/* Check use of sysconf() for cache geometries.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* Test use of sysconf() to get cache sizes, cache set associativity
+ and cache line sizes. */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <support/test-driver.h>
+
+#define call_str(f, name) f(name, #name)
+
+long
+do_sysconf (int name, const char * str)
+{
+ int rc = 0;
+ long val;
+ printf ("sysconf(%s)", str);
+ errno = 0;
+ val = sysconf (name);
+ if (val == -1) {
+ if (errno != EINVAL) {
+ printf(" unexpected errno(%d)\n", errno);
+ exit (EXIT_FAILURE);
+ }
+ printf (" is unsupported\n");
+ rc = 1;
+ } else
+ printf (" = 0x%lx (%ld)\n", val, val);
+ return rc;
+}
+
+static int
+do_test (void)
+{
+ int rc = 0;
+
+ rc += call_str (do_sysconf, _SC_LEVEL1_ICACHE_SIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL1_ICACHE_ASSOC);
+ rc += call_str (do_sysconf, _SC_LEVEL1_ICACHE_LINESIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL1_DCACHE_SIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL1_DCACHE_ASSOC);
+ rc += call_str (do_sysconf, _SC_LEVEL1_DCACHE_LINESIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL2_CACHE_SIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL2_CACHE_ASSOC);
+ rc += call_str (do_sysconf, _SC_LEVEL2_CACHE_LINESIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL3_CACHE_SIZE);
+ rc += call_str (do_sysconf, _SC_LEVEL3_CACHE_ASSOC);
+ rc += call_str (do_sysconf, _SC_LEVEL3_CACHE_LINESIZE);
+
+ if (rc)
+ return EXIT_UNSUPPORTED;
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"