155 lines
6.0 KiB
Diff
155 lines
6.0 KiB
Diff
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Upstream-Status: Backport
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From ca6d916a6f8f0f8abbb4c9b6a97dd1a1615bb124 Mon Sep 17 00:00:00 2001
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From: Maynard Johnson <maynardj@us.ibm.com>
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Date: Wed, 5 Dec 2012 10:16:35 -0600
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Subject: [PATCH] Fix up configure to handle architectures that do not
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implement perf_event_open
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This patch fixes the following problems:
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1) The configure script allows the user to pass a location to kernel
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headers (via --with-kernel option) such that, even if the running
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kernel does not have perf_events support, it may be possible to
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build operf (e.g., in cross-compile environments). But the message
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'This kernel does not have perf_events support; falling back to legacy
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oprofile' was being displayed inappropriately in such cases. This
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patch changes the configure script so that the "falling back to
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legacy oprofile" message will only be displayed if we're running
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on a kernel that does not have perf_events support AND the user
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did not pass specify the "--with-kernel" option.
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2) Some architectures don't even implement the perf_event_open syscall, so the
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configure script must do more than checking kernel version and whether or not
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perf_event.h is present in order to decide if perf_events is supported.
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This patch provides that extra capability.
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These problems were reported by Tony Jones <tonyj@suse.com>.
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Signed-off-by: Maynard Johnson <maynardj@us.ibm.com>
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---
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configure.ac | 74 +++++++++++++++++++++++++++++-----------
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utils/op_perf_events_checker.c | 6 ++--
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2 files changed, 58 insertions(+), 22 deletions(-)
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diff --git a/configure.ac b/configure.ac
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--- a/configure.ac
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+++ b/configure.ac
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@@ -70,35 +70,70 @@ KERNELDIR=$withval)
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dnl Check kernel version for perf_events supported
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-AC_MSG_CHECKING([kernel version supports perf_events])
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if test "$KERNELDIR" != ""; then
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KINC="$KERNELDIR/include"
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+ PERF_EVENT_FLAGS=" -I$KERNELDIR/include"
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+ AC_SUBST(PERF_EVENT_FLAGS)
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+ PERF_EVENT_H="$KERNELDIR/include/linux/perf_event.h"
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+else
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+ PERF_EVENT_H="/usr/include/linux/perf_event.h"
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fi
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-AX_KERNEL_VERSION(2, 6, 31, <=, kernel_has_perf_events_support="yes",
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+
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+PERF_EVENT_H_EXISTS="no"
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+kernel_may_have_perf_events_support="no"
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+AX_KERNEL_VERSION(2, 6, 31, <=, kernel_may_have_perf_events_support="yes",
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kernel_has_perf_events_support="no")
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-if test "$kernel_has_perf_events_support" = "no"; then
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- AC_MSG_RESULT([This kernel does not have perf_events support; falling back to legacy oprofile])
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+dnl The AX_KERNEL_VERSION macro may return kernel_may_have_perf_events_support="yes",
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+dnl indicating a partial answer. Some architectures do not implement the Performance
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+dnl Events Kernel Subsystem even with kernel versions > 2.6.31 -- i.e., not even
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+dnl implementing the perf_event_open syscall to return ENOSYS. So the check below
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+dnl will identify and handle such situations.
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+
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+if test "$kernel_may_have_perf_events_support" = "yes"; then
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+ AC_CHECK_HEADER($PERF_EVENT_H,PERF_EVENT_H_EXISTS="yes")
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+ AC_MSG_CHECKING([kernel supports perf_events])
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+ if test "$PERF_EVENT_H_EXISTS" = "yes"; then
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+ rm -f test-for-PERF_EVENT_OPEN
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+ AC_LANG_CONFTEST(
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+ [AC_LANG_PROGRAM([[#include <linux/perf_event.h>
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+ #include <asm/unistd.h>
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+ #include <sys/types.h>
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+ #include <string.h>
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+ ]],
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+ [[struct perf_event_attr attr;
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+ pid_t pid;
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+ memset(&attr, 0, sizeof(attr));
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+ attr.size = sizeof(attr);
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+ attr.sample_type = PERF_SAMPLE_IP;
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+ pid = getpid();
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+ syscall(__NR_perf_event_open, &attr, pid, 0, -1, 0);
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+ ]])
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+ ])
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+ $CC conftest.$ac_ext $CFLAGS $LDFLAGS $LIBS $PERF_EVENT_FLAGS -o test-for-PERF_EVENT_OPEN > /dev/null 2>&1
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+ if test -f test-for-PERF_EVENT_OPEN; then
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+ kernel_has_perf_events_support="yes"
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+ AC_MSG_RESULT(yes)
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+ else
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+ AC_MSG_RESULT(no)
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+ kernel_has_perf_events_support="no"
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+ fi
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+ else
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+ AC_MSG_RESULT(unknown -- perf_event.h not found)
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+ fi
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else
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- AC_MSG_RESULT([This kernel has perf_events support])
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+ AC_MSG_RESULT(kernel supports perf_events... no)
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+ kernel_has_perf_events_support="no"
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+fi
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+AM_CONDITIONAL(BUILD_FOR_PERF_EVENT, test "$kernel_has_perf_events_support" = "yes")
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+
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+if test "$kernel_has_perf_events_support" = "yes"; then
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+ HAVE_PERF_EVENTS='1'
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+else
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+ HAVE_PERF_EVENTS='0'
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+ AC_MSG_RESULT([No perf_events support available; falling back to legacy oprofile])
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fi
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-if test "$KERNELDIR" == ""; then
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- PERF_EVENT_H="/usr/include/linux/perf_event.h"
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-else
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- PERF_EVENT_H="$KERNELDIR/include/linux/perf_event.h"
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-fi
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-AC_CHECK_HEADER($PERF_EVENT_H,PERF_EVENT_H_EXISTS="yes")
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-AM_CONDITIONAL(BUILD_FOR_PERF_EVENT, test -n "$PERF_EVENT_H_EXISTS")
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-if test "$PERF_EVENT_H_EXISTS" = "yes"; then
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- HAVE_PERF_EVENTS='1'
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- if test "$KERNELDIR" != ""; then
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- PERF_EVENT_FLAGS=" -I$KERNELDIR/include"
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- AC_SUBST(PERF_EVENT_FLAGS)
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- fi
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-else
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- HAVE_PERF_EVENTS='0'
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-fi
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AC_DEFINE_UNQUOTED(HAVE_PERF_EVENTS, $HAVE_PERF_EVENTS, [Kernel support for perf_events exists])
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AC_CANONICAL_HOST
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if test "$HAVE_PERF_EVENTS" = "1"; then
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@@ -414,7 +449,7 @@ elif test "`getent passwd oprofile 2>/de
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fi
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fi
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-if test "$PERF_EVENT_H_EXISTS" != "yes" && test "$kernel_has_perf_events_support" = "yes"; then
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+if test "$PERF_EVENT_H_EXISTS" != "yes" && test "$kernel_may_have_perf_events_support" = "yes"; then
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echo "Warning: perf_event.h not found. Please install the kernel headers package if you"
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echo " want non-root support built into OProfile."
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fi
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diff --git a/utils/op_perf_events_checker.c b/utils/op_perf_events_checker.c
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--- a/utils/op_perf_events_checker.c
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+++ b/utils/op_perf_events_checker.c
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@@ -49,8 +49,10 @@ int main(int argc, char **argv)
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}
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#if HAVE_PERF_EVENTS
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- /* If perf_events syscall is not implemented, the syscall below will fail
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- * with ENOSYS (38). If implemented, but the processor type on which this
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+ /* Even if the perf_event_open syscall is implemented, the architecture may still
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+ * not provide a full implementation of the perf_events subsystem, in which case,
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+ * the syscall below will fail with ENOSYS (38). If the perf_events subsystem is
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+ * implemented for the architecture, but the processor type on which this
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* program is running is not supported by perf_events, the syscall returns
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* ENOENT (2).
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*/
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