From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nathan_Lynch@mentor.com (Nathan Lynch) Date: Fri, 18 Apr 2014 12:48:23 -0500 Subject: Perf top always show 0.00 In-Reply-To: References: Message-ID: <53516567.10405@mentor.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/18/2014 12:00 PM, Frank Li wrote: > I use mx6dq platform. Found below problem. > > Run Perf top. First column always 0, but order look like correct. > > 0.00% perf [.] 0x00049420 > 0.00% [kernel] [k] kallsyms_expand_symbol.constprop.5 > 0.00% [kernel] [k] vsnprintf > 0.00% [kernel] [k] arch_cpu_idle > 0.00% [kernel] [k] format_decode > 0.00% [kernel] [k] number.isra.2 > 0.00% libc-2.19.so [.] strstr > 0.00% libc-2.19.so [.] 0x00072498 > 0.00% libc-2.19.so [.] memchr > 0.00% [kernel] [k] _raw_spin_unlock_irqrestore > 0.00% [kernel] [k] string.isra.4 > 0.00% [kernel] [k] strnlen > 0.00% libc-2.19.so [.] getdelim > 0.00% libc-2.19.so [.] memcpy > 0.00% [kernel] [k] lock_acquire > 0.00% libc-2.19.so [.] strchr > 0.00% libc-2.19.so [.] strcmp > 0.00% [kernel] [k] _raw_spin_unlock_irq > 0.00% libc-2.19.so [.] __libc_calloc > 0.00% libc-2.19.so [.] _IO_feof > 0.00% [kernel] [k] pointer.isra.15 The PMU is possibly worthless: http://lists.infradead.org/pipermail/linux-arm-kernel/2012-August/113802.html http://lists.infradead.org/pipermail/linux-arm-kernel/2013-February/151945.html