From dd77038d233d106f297b907bf51459dfb1099eb1 Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Fri, 30 Oct 2009 19:32:25 -0200 Subject: [PATCH 1/2] perf_events: Fix some typo in the perf events config description Signed-off-by: Thadeu Lima de Souza Cascardo Cc: trivial@kernel.org LKML-Reference: <1256938346-8230-1-git-send-email-cascardo@holoscopio.com> Signed-off-by: Ingo Molnar --- init/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 09c5c6431f4..3b8c7bc943b 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -937,7 +937,7 @@ config PERF_EVENTS Enable kernel support for various performance events provided by software and hardware. - Software events are supported either build-in or via the + Software events are supported either built-in or via the use of generic tracepoints. Most modern CPUs support performance events via performance @@ -949,7 +949,7 @@ config PERF_EVENTS used to profile the code that runs on that CPU. The Linux Performance Event subsystem provides an abstraction of - these software and hardware cevent apabilities, available via a + these software and hardware event capabilities, available via a system call and used by the "perf" utility in tools/perf/. It provides per task and per CPU counters, and it provides event capabilities on top of those. From c10edee2e1716f8cf217cf52ed01ae4742fcdf3c Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Sun, 8 Nov 2009 18:01:06 +0200 Subject: [PATCH 2/2] perf tools: Fix permission checks The perf_event_open() system call returns EACCES if the user is not root which results in a very confusing error message: $ perf record -A -a -f Error: perfcounter syscall returned with -1 (Permission denied) Fatal: No CONFIG_PERF_EVENTS=y kernel support configured? It turns out that's because perf tools are checking only for EPERM. Fix that up to get a much better error message: $ perf record -A -a -f Fatal: Permission error - are you root? Signed-off-by: Pekka Enberg Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Frederic Weisbecker LKML-Reference: <1257696066-4046-1-git-send-email-penberg@cs.helsinki.fi> Signed-off-by: Ingo Molnar --- tools/perf/builtin-record.c | 2 +- tools/perf/builtin-top.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 3eeef339c78..a4be453fc8a 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -426,7 +426,7 @@ try_again: if (fd[nr_cpu][counter] < 0) { int err = errno; - if (err == EPERM) + if (err == EPERM || err == EACCES) die("Permission error - are you root?\n"); else if (err == ENODEV && profile_cpu != -1) die("No such device - did you specify an out-of-range profile CPU?\n"); diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index a1b1d10912d..e23bc74e734 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1027,7 +1027,7 @@ try_again: if (fd[i][counter] < 0) { int err = errno; - if (err == EPERM) + if (err == EPERM || err == EACCES) die("No permission - are you root?\n"); /* * If it's cycles then fall back to hrtimer