-----Original Message----- From: Peter Krempa [mailto:pkrempa@redhat.com] Sent: Thursday, June 9, 2016 7:50 PM To: Ren, Qiaowei <qiaowei.ren@intel.com> Cc: libvir-list@redhat.com Subject: Re: [libvirt] [PATCH 1/1] perf: add more perf events support
On Tue, May 31, 2016 at 10:48:15 +0800, Qiaowei Ren wrote:
With current perf framework, this patch adds support to more perf events, including cache missing, cache peference, cpu cycles, instrction, etc..
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com> --- include/libvirt/libvirt-domain.h | 39 ++++++++++++++++++++++++ src/libvirt-domain.c | 8 +++++ src/qemu/qemu_driver.c | 23 +++++++------- src/util/virperf.c | 65 +++++++++++++++++++++++++++++++++++++++- src/util/virperf.h | 4 +++ 5 files changed, 126 insertions(+), 13 deletions(-)
diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h index cba4fa5..99c4c48 100644 --- a/include/libvirt/libvirt-domain.h +++ b/include/libvirt/libvirt-domain.h @@ -1928,6 +1928,45 @@ void virDomainStatsRecordListFree(virDomainStatsRecordPtr *stats); */ # define VIR_PERF_PARAM_MBML "mbml"
[...]
+/** + * VIR_PERF_PARAM_INSTRUCTIONS: + * + * Macro for typed parameter name that represents instructions perf + * event which can be used to measure the amount of instructions + * by applications running on the platform. It corresponds to the + * "perf.instructions" field in the *Stats APIs.
I'm not sure if I understand the implications and usability of this stat parameter. Could you elaborate on how this can be used?
+ */ +# define VIR_PERF_PARAM_INSTRUCTIONS "instructions" + +/** + * VIR_PERF_PARAM_CPU_CYCLES: + * + * Macro for typed parameter name that represents cpu_cycles perf +event + * which can be used to measure how many cycles one instruction needs. + * It corresponds to the "perf.cpu_cycles" field in the *Stats APIs.
And same for this. I don't really see how this can be used.
Peter, thanks for your feedback! Instructions and cycles can be used to gain IPC (Instructions Per Clock, = Instructions/Cycles), and a low IPC ratio indicates the code of the process makes poor use of the CPU. Thanks, Qiaowei