On Tue, Jan 08, 2019 at 11:48:41AM +0100, Peter Zijlstra wrote: > On Mon, Jan 07, 2019 at 04:27:27PM +0000, Andrew Murray wrote: > > For drivers that do not support context exclusion let's advertise the > > PERF_PMU_CAP_NOEXCLUDE capability. This ensures that perf will > > prevent us from handling events where any exclusion flags are set. > > Let's also remove the now unnecessary check for exclusion flags. > > > > Signed-off-by: Andrew Murray <andrew.murray@xxxxxxx> > > --- > > arch/x86/events/amd/ibs.c | 13 +------------ > > arch/x86/events/amd/power.c | 10 ++-------- > > arch/x86/events/intel/cstate.c | 12 +++--------- > > arch/x86/events/intel/rapl.c | 9 ++------- > > arch/x86/events/intel/uncore_snb.c | 9 ++------- > > arch/x86/events/msr.c | 10 ++-------- > > 6 files changed, 12 insertions(+), 51 deletions(-) > > You (correctly) don't add CAP_NO_EXCLUDE to the main x86 pmu code, but > then you also don't check if it handles all the various exclude options > correctly/consistently. > > Now; I must admit that that is a bit of a maze, but I think we can at > least add exclude_idle and exclude_hv fails in there, nothing uses those > afaict. Yes it took me some time to make sense of it. As per my comments in the other patch, I think you're suggesting that I add additional checks to x86. I think they are needed but I'd prefer to make functional changes in a separate series, I'm happy to do this. > > On the various exclude options; they are as follows (IIUC): > > - exclude_guest: we're a HV/host-kernel and we don't want the counter > to run when we run a guest context. > > - exclude_host: we're a HV/host-kernel and we don't want the counter > to run when we run in host context. > > - exclude_hv: we're a guest and don't want the counter to run in HV > context. > > Now, KVM always implies exclude_hv afaict (for guests), It certaintly does for ARM. > I'm not sure > what, if anything Xen does on x86 (IIRC Brendan Gregg once said perf > works on Xen) -- nor quite sure who to ask, Boris, Jeurgen? Thanks, Andrew Murray >
