From: Prarit Bhargava prarit@redhat.com
[ Upstream commit 40aafc7d58d3544f152a863a0e9863014b6d5d8c ]
When running as non-root the following error is seen in turbostat:
turbostat: fopen /dev/cpu_dma_latency : Permission denied
turbostat and the man page have information on how to avoid other permission errors, so these can be fixed the same way.
Provide better /dev/cpu_dma_latency warnings that provide instructions on how to avoid the error, and update the man page.
Signed-off-by: Prarit Bhargava prarit@redhat.com Cc: linux-pm@vger.kernel.org Signed-off-by: Len Brown len.brown@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/power/x86/turbostat/turbostat.8 | 2 ++ tools/power/x86/turbostat/turbostat.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8 index f6b7e85b121ce..71e3f3a68b9df 100644 --- a/tools/power/x86/turbostat/turbostat.8 +++ b/tools/power/x86/turbostat/turbostat.8 @@ -294,6 +294,8 @@ Alternatively, non-root users can be enabled to run turbostat this way:
# chmod +r /dev/cpu/*/msr
+# chmod +r /dev/cpu_dma_latency + .B "turbostat " reads hardware counters, but doesn't write them. So it will not interfere with the OS or other programs, including diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index ef65f7eed1ec9..d33c9d427e573 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -5004,7 +5004,7 @@ void print_dev_latency(void)
retval = read(fd, (void *)&value, sizeof(int)); if (retval != sizeof(int)) { - warn("read %s\n", path); + warn("read failed %s\n", path); close(fd); return; }