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Commit 9236e872 authored by Connor O'Brien's avatar Connor O'Brien
Browse files

libtimeinstate: support cpufreq fast switching 



In order to support kernels that use fast frequency switching, the
time_in_state BPF program needs to know which CPUs are members of
which cpufreq policies. Add logic to startTrackingUidCpuFreqTimes() to
write this information into a BPF map in order to make it available to
the BPF program.

Test: libtimeinstate_test passes
Change-Id: I47b38457766d21c2aa0879f156fc90757c0db705
Signed-off-by: default avatarConnor O'Brien <connoro@google.com>
parent 6c501ea0

libs/cputimeinstate/cputimeinstate.cpp

+11 −0
Original line number Diff line number Diff line
@@ -141,6 +141,17 @@ static bool attachTracepointProgram(const std::string &eventType, const std::str 
// This function should *not* be called while tracking is already active; doing so is unnecessary

// and can lead to accounting errors.

bool startTrackingUidCpuFreqTimes() {

    if (!initGlobals()) return false;



    unique_fd fd(bpf_obj_get(BPF_FS_PATH "map_time_in_state_cpu_policy_map"));

    if (fd < 0) return false;



    for (uint32_t i = 0; i < gPolicyCpus.size(); ++i) {

        for (auto &cpu : gPolicyCpus[i]) {

            if (writeToMapEntry(fd, &cpu, &i, BPF_ANY)) return false;

        }

    }



    return attachTracepointProgram("sched", "sched_switch") &&

            attachTracepointProgram("power", "cpu_frequency");

}