public void process() {
        // Check agent information
        if (StringUtils.isEmpty(service) || StringUtil.isEmpty(serviceInstance) || timestamp == null) {
            return;
        }

        // Get all meter builders.
        final List<MetricConvert> converts = processService.converts();
        if (CollectionUtils.isEmpty(converts)) {
            return;
        }

        try {
            converts.forEach(convert -> convert.toMeter(meters.entrySet().stream().collect(toImmutableMap(
                Map.Entry::getKey,
                v -> SampleFamilyBuilder.newBuilder(
                    v.getValue().stream().map(s -> s.build(service, serviceInstance, timestamp)).toArray(Sample[]::new)
                ).defaultHistogramBucketUnit(TimeUnit.MILLISECONDS).build()
            ))));
        } catch (Exception e) {
            log.warn("Process meters failure.", e);
        }
    }
Process all of meters and send to meter system.
oap-server/analyzer/agent-analyzer/src/main/java/org/apache/skywalking/oap/server/analyzer/provider/meter/process/MeterProcessor.java