diff --git a/frontend/src/components/charts/timeSeriesGap.ts b/frontend/src/components/charts/timeSeriesGap.ts
new file mode 100644
index 000000000..05cb773fc
--- /dev/null
+++ b/frontend/src/components/charts/timeSeriesGap.ts
@@ -0,0 +1,121 @@
+import type { LineSeriesOption } from 'echarts'
+
+type TemporalValue = number | null | undefined
+
+interface GapRun {
+  startIndex: number
+  endIndex: number
+}
+
+interface GapBridgeOptions {
+  name: string
+  color: string
+  xAxisIndex?: number
+  yAxisIndex?: number
+  width?: number
+  z?: number
+  maxGapBuckets?: number
+}
+
+const defaultShortGapBuckets = 2
+
+export function sampleGapBridgeSeries(
+  values: TemporalValue[],
+  options: GapBridgeOptions,
+): LineSeriesOption[] {
+  const data = values.map(normalizeValue)
+  const maxGapBuckets = options.maxGapBuckets ?? defaultShortGapBuckets
+  const series: LineSeriesOption[] = []
+
+  for (const [runIndex, run] of boundedGapRuns(data)
+    .filter(run => gapLength(run) <= maxGapBuckets)
+    .entries()) {
+    const beforeIndex = run.startIndex - 1
+    const afterIndex = run.endIndex + 1
+    const beforeValue = data[beforeIndex]
+    const afterValue = data[afterIndex]
+    const bridge = Array.from<number | null>({ length: data.length }).fill(null)
+
+    if (beforeValue == null || afterValue == null)
+      continue
+
+    const span = afterIndex - beforeIndex
+    for (let index = beforeIndex; index <= afterIndex; index += 1) {
+      const progress = (index - beforeIndex) / span
+      bridge[index] = beforeValue + (afterValue - beforeValue) * progress
+    }
+
+    series.push({
+      name: `${options.name}-gap-${runIndex}`,
+      type: 'line',
+      data: bridge,
+      connectNulls: false,
+      smooth: false,
+      showSymbol: false,
+      silent: true,
+      xAxisIndex: options.xAxisIndex ?? 0,
+      yAxisIndex: options.yAxisIndex ?? 0,
+      z: Math.max(0, (options.z ?? 2) - 1),
+      lineStyle: {
+        color: options.color,
+        type: 'dashed',
+        width: Math.max(1, (options.width ?? 2.2) - 0.7),
+        opacity: 0.32,
+      },
+      itemStyle: { color: options.color, opacity: 0 },
+      emphasis: { disabled: true },
+      tooltip: { show: false },
+    })
+  }
+
+  return series
+}
+
+export function requestActivityByBucket(
+  buckets: string[],
+  activity: Array<{ bucket: string, totalRequests: number }>,
+) {
+  const requestsByBucket = new Map(
+    activity.map(point => [point.bucket, Math.max(0, point.totalRequests)]),
+  )
+  return buckets.map(bucket => (requestsByBucket.get(bucket) ?? 0) > 0)
+}
+
+export function zeroInactiveValues(
+  values: TemporalValue[],
+  active: boolean[],
+) {
+  return values.map((value, index) => normalizeValue(value) ?? (active[index] === false ? 0 : null))
+}
+
+function normalizeValue(value: TemporalValue) {
+  return typeof value === 'number' && Number.isFinite(value) ? value : null
+}
+
+function boundedGapRuns(values: Array<number | null>) {
+  return gapRuns(values.map(value => value == null)).filter(
+    run => run.startIndex > 0 && run.endIndex < values.length - 1,
+  )
+}
+
+function gapRuns(isGap: boolean[]) {
+  const runs: GapRun[] = []
+  let startIndex = -1
+
+  for (let index = 0; index <= isGap.length; index += 1) {
+    if (isGap[index] && startIndex < 0) {
+      startIndex = index
+      continue
+    }
+    if (isGap[index] || startIndex < 0)
+      continue
+    runs.push({ startIndex, endIndex: index - 1 })
+    startIndex = -1
+  }
+
+  return runs
+}
+
+function gapLength(run: GapRun) {
+  return run.endIndex - run.startIndex + 1
+}
diff --git a/frontend/src/views/dashboard/composables/useDashboard.ts b/frontend/src/views/dashboard/composables/useDashboard.ts
index 81f6a24fa..9e53e24ec 100644
--- a/frontend/src/views/dashboard/composables/useDashboard.ts
+++ b/frontend/src/views/dashboard/composables/useDashboard.ts
@@ -373,10 +373,10 @@ function aggregateUsageTrend(points: DashboardTrendPoint[]) {
     )
     const uncachedInputTokensValue = inputTokensValue - cachedTokensValue
     const effectiveTokensValue = uncachedInputTokensValue + outputTokensValue
-    const cacheHitRateValue = inputTokensValue ? cachedTokensValue / inputTokensValue : null
+    const cacheHitRateValue = inputTokensValue ? cachedTokensValue / inputTokensValue : 0
     const successRateValue = requestsValue
       ? ((requestsValue - errorsValue) / requestsValue) * 100
-      : null
+      : 0
 
     return {
       ...first,
@@ -392,12 +392,12 @@ function aggregateUsageTrend(points: DashboardTrendPoint[]) {
       uncachedInputTokensValue,
       effectiveTokens: formatCompactNumber(effectiveTokensValue),
       effectiveTokensValue: effectiveTokensValue > 0 ? effectiveTokensValue : null,
-      cacheHitRate: cacheHitRateValue === null ? '—' : formatDashboardRate(cacheHitRateValue),
+      cacheHitRate: formatDashboardRate(cacheHitRateValue),
       cacheHitRateValue,
       tokensValue: inputTokensValue + outputTokensValue,
       errors: formatCompactNumber(errorsValue),
       errorsValue,
-      successRate: successRateValue === null ? '—' : `${successRateValue.toFixed(1)}%`,
+      successRate: `${successRateValue.toFixed(1)}%`,
       successRateValue,
     }
   })
diff --git a/frontend/src/views/dashboard/composables/useRequestTrendChart.ts b/frontend/src/views/dashboard/composables/useRequestTrendChart.ts
index 23cc0f0b3..e5d4e5d8e 100644
--- a/frontend/src/views/dashboard/composables/useRequestTrendChart.ts
+++ b/frontend/src/views/dashboard/composables/useRequestTrendChart.ts
@@ -4,6 +4,7 @@ import type { dashboardTrendView, normalizeDashboardTrendKind } from './useDashb
 import { usePreferredReducedMotion } from '@vueuse/core'
 import { computed, shallowRef, watch } from 'vue'
 
+import { sampleGapBridgeSeries } from '@/components/charts/timeSeriesGap'
 import { chartTooltipStyle, tooltipIndex } from '@/components/charts/tooltip'
 import { useChartPalette } from '@/composables/useChartPalette'
 
@@ -197,7 +198,7 @@ export function useRequestTrendChart(options: {
         ),
         tooltipItem(
           '缓存命中',
-          trendPointText(point, 'cacheHitRate'),
+          zeroAwareRateText(point, 'cacheHitRate', 'inputTokensValue'),
           trendColor('缓存', '--cp-color-text-tertiary', '#94A3B8'),
         ),
         tooltipItem('请求', point?.requests, palette.value.textSecondary),
@@ -235,19 +236,19 @@ export function useRequestTrendChart(options: {
     if (name === '错误数')
       return point?.errors ?? value
     if (name === '成功率')
-      return point?.successRate ?? value
+      return zeroAwareRateText(point, 'successRate', 'requestsValue') ?? value
     if (name === '总请求')
       return point?.requests ?? value
     return value
   }
 
-  function getSeries() {
+  function getSeries(): Array<BarSeriesOption | LineSeriesOption> {
     if (activeKind.value === 'usage') {
       const cacheColor = trendColor('缓存', '--cp-color-text-tertiary', '#94A3B8')
       const inputColor = trendColor('输入', '--cp-color-blue-solid', '#5983F4')
       const outputColor = trendColor('输出', '--cp-color-green-solid', '#12B981')
       return [
-        lineSeries('缓存', activeSeriesValues('cachedTokensValue'), cacheColor, {
+        lineSeries('缓存', seriesValues('cachedTokensValue'), cacheColor, {
           area: true,
           areaStartAlpha: '30',
           areaEndAlpha: '08',
@@ -257,7 +258,7 @@ export function useRequestTrendChart(options: {
           width: 1.25,
           z: 1,
         }),
-        lineSeries('输入', activeSeriesValues('uncachedInputTokensValue'), inputColor, {
+        lineSeries('输入', seriesValues('uncachedInputTokensValue'), inputColor, {
           area: true,
           areaStartAlpha: '2A',
           areaEndAlpha: '05',
@@ -266,7 +267,7 @@ export function useRequestTrendChart(options: {
           width: 2.3,
           z: 3,
         }),
-        lineSeries('输出', activeSeriesValues('outputTokensValue'), outputColor, {
+        lineSeries('输出', seriesValues('outputTokensValue'), outputColor, {
           smooth: 0.24,
           width: 2.1,
           yAxisIndex: 1,
@@ -277,19 +278,19 @@ export function useRequestTrendChart(options: {
 
     if (activeKind.value === 'latency') {
       return [
-        lineSeries(
+        ...gapLineSeries(
           '总耗时 P95',
           activeSeriesValues('latencyP95Ms'),
           trendColor('总耗时', '--cp-color-orange-solid', '#F59E0B'),
           { lineType: 'dashed', smooth: 0.2, width: 1.8, z: 2 },
         ),
-        lineSeries(
+        ...gapLineSeries(
           '首字 P95',
           activeSeriesValues('firstTokenP95Ms'),
           trendColor('首字', '--cp-color-cyan-solid', '#13C2C2'),
           { area: true, smooth: 0.24, width: 2.5, z: 4 },
         ),
-        lineSeries(
+        ...gapLineSeries(
           '吞吐 P50',
           activeSeriesValues('outputThroughputP50'),
           trendColor('吞吐', '--cp-color-green-solid', '#12B981'),
@@ -304,9 +305,9 @@ export function useRequestTrendChart(options: {
         seriesValues('errorsValue'),
         trendColor('错误', '--cp-color-red-solid', '#EF4444'),
       ),
-      lineSeries(
+      ...gapLineSeries(
         '成功率',
-        seriesValues('successRateValue'),
+        activeSeriesValues('successRateValue'),
         trendColor('成功', '--cp-color-green-solid', '#12B981'),
         { width: 2.4, yAxisIndex: 1 },
       ),
@@ -325,7 +326,7 @@ export function useRequestTrendChart(options: {
 
   function activeSeriesValues(key: string) {
     return points.value.map(point =>
-      Number(point.requestsValue) > 0 ? trendPointNumber(point, key) : null,
+      Number(point.requestsValue) > 0 ? trendPointNumber(point, key) : 0,
     )
   }
 
@@ -377,6 +378,26 @@ export function useRequestTrendChart(options: {
     }
   }
 
+  function gapLineSeries(
+    name: string,
+    data: (number | null)[],
+    color: string,
+    lineOptions: LineSeriesOptions = {},
+  ) {
+    const primary = lineSeries(name, data, color, lineOptions)
+    return [
+      primary,
+      ...sampleGapBridgeSeries(data, {
+        name,
+        color,
+        width: lineOptions.width,
+        xAxisIndex: lineOptions.xAxisIndex,
+        yAxisIndex: lineOptions.yAxisIndex,
+        z: lineOptions.z,
+      }),
+    ]
+  }
+
   function barSeries(
     name: string,
     data: (number | null)[],
@@ -490,7 +511,7 @@ function tooltipValue(source: unknown, key: string) {
 function trendPointProperty(point: TrendPoint | undefined, key: string) {
   if (!point || !(key in point))
     return undefined
-  return (point as Record<string, unknown>)[key]
+  return (point as unknown as Record<string, unknown>)[key]
 }
 
 function trendPointText(point: TrendPoint | undefined, key: string) {
@@ -498,6 +519,17 @@ function trendPointText(point: TrendPoint | undefined, key: string) {
   return typeof value === 'string' ? value : undefined
 }
 
+function zeroAwareRateText(
+  point: TrendPoint | undefined,
+  valueKey: string,
+  activityKey: string,
+) {
+  const activity = trendPointProperty(point, activityKey)
+  if (typeof activity === 'number' && activity <= 0)
+    return '0.0%'
+  return trendPointText(point, valueKey)
+}
+
 function trendPointNumber(point: TrendPoint, key: string) {
   const value = trendPointProperty(point, key)
   return typeof value === 'number' && Number.isFinite(value) ? value : null
diff --git a/frontend/src/views/usage/components/UsageCostCard.vue b/frontend/src/views/usage/components/UsageCostCard.vue
index 0ab69ef2c..b7d6251d9 100644
--- a/frontend/src/views/usage/components/UsageCostCard.vue
+++ b/frontend/src/views/usage/components/UsageCostCard.vue
@@ -7,6 +7,10 @@ import BaseCard from '@/components/base/BaseCard.vue'
 import BaseEmpty from '@/components/base/BaseEmpty.vue'
 import BaseSegmented from '@/components/base/BaseSegmented.vue'
 import BaseChart from '@/components/charts/BaseChart.vue'
+import {
+  requestActivityByBucket,
+  zeroInactiveValues,
+} from '@/components/charts/timeSeriesGap'
 import { useChartPalette } from '@/composables/useChartPalette'
 import { formatLocalizedCompactNumber as formatCompactNumber } from '@/utils/number'
 
@@ -14,10 +18,11 @@ import {
   tooltipIndex,
   tooltipRows,
   usageCategoryAxis,
+  usageGapAwareLineSeries,
   usageLegend,
-  usageLineSeries,
   usageTooltip,
   usageTooltipContent,
+  usageTooltipItem,
   usageValueAxis,
 } from '../utils/chart'
 import {
@@ -28,11 +33,13 @@ import {
 } from '../utils/format'
 
 type Cost = Awaited<ReturnType<typeof getUsageRecordInsightsOverview>>['cost']
+type Activity = Awaited<ReturnType<typeof getUsageRecordInsightsOverview>>['health']['points']
 type UsageChartPalette = ReturnType<typeof useChartPalette>['palette']['value']
 
 const props = withDefaults(
   defineProps<{
     cost: Cost
+    activity: Activity
     loading?: boolean
   }>(),
   {
@@ -43,6 +50,10 @@ const props = withDefaults(
 const activeView = shallowRef('cost')
 const { palette } = useChartPalette()
 const points = computed(() => props.cost.points)
+const requestActivity = computed(() => requestActivityByBucket(
+  points.value.map(point => point.bucket),
+  props.activity,
+))
 const hasNoCacheCost = computed(() =>
   points.value.some(point => point.noCacheCost != null),
 )
@@ -74,6 +85,7 @@ const hasData = computed(() => {
 const chartOption = computed<EChartsOption>(() => {
   const theme = palette.value
   const legend = legendNames()
+  const series = chartSeries(theme)
 
   return {
     animationDuration: 240,
@@ -95,7 +107,7 @@ const chartOption = computed<EChartsOption>(() => {
       min: activeView.value === 'cache' ? 0 : undefined,
       max: activeView.value === 'cache' ? 1 : undefined,
     }),
-    series: chartSeries(theme),
+    series,
   }
 })
 
@@ -119,9 +131,12 @@ function chartSeries(theme: UsageChartPalette): LineSeriesOption[] {
   const chartPoints = points.value
   if (activeView.value === 'savings') {
     return [
-      usageLineSeries(
+      ...usageGapAwareLineSeries(
         '缓存节省',
-        chartPoints.map(point => decimalDisplayNumber(point.cacheSavings)),
+        zeroInactiveValues(
+          chartPoints.map(point => decimalDisplayNumber(point.cacheSavings)),
+          requestActivity.value,
+        ),
         theme.success,
         { area: 'strong' },
       ),
@@ -130,12 +145,12 @@ function chartSeries(theme: UsageChartPalette): LineSeriesOption[] {
 
   if (activeView.value === 'cache') {
     return [
-      usageLineSeries(
+      ...usageGapAwareLineSeries(
         '缓存 Token 占比',
         chartPoints.map(point => point.cachedTokenRate),
         theme.normal,
       ),
-      usageLineSeries(
+      ...usageGapAwareLineSeries(
         '命中请求率',
         chartPoints.map(point => point.cacheHitRequestRate),
         theme.success,
@@ -144,18 +159,24 @@ function chartSeries(theme: UsageChartPalette): LineSeriesOption[] {
   }
 
   const series = [
-    usageLineSeries(
+    ...usageGapAwareLineSeries(
       '实际费用',
-      chartPoints.map(point => decimalDisplayNumber(point.estimatedCost)),
+      zeroInactiveValues(
+        chartPoints.map(point => decimalDisplayNumber(point.estimatedCost)),
+        requestActivity.value,
+      ),
       theme.success,
       { area: 'strong' },
     ),
   ]
   if (hasNoCacheCost.value) {
     series.push(
-      usageLineSeries(
+      ...usageGapAwareLineSeries(
         '无缓存费用',
-        chartPoints.map(point => decimalDisplayNumber(point.noCacheCost)),
+        zeroInactiveValues(
+          chartPoints.map(point => decimalDisplayNumber(point.noCacheCost)),
+          requestActivity.value,
+        ),
         theme.textMuted,
       ),
     )
@@ -165,29 +186,48 @@ function chartSeries(theme: UsageChartPalette): LineSeriesOption[] {
 
 function formatTooltip(params: unknown) {
   const rows = tooltipRows(params)
-  const point = points.value[tooltipIndex(rows[0])]
+  const pointIndex = tooltipIndex(rows[0])
+  const point = points.value[pointIndex]
   if (!point)
     return ''
+  const theme = palette.value
 
   if (activeView.value === 'savings') {
-    return usageTooltipContent(palette.value, point.label, [
-      `缓存节省: ${formatUsd(point.cacheSavings)}`,
+    return usageTooltipContent(theme, point.label, [
+      usageTooltipItem(
+        '缓存节省',
+        formatUsd(costAmount(point.cacheSavings, pointIndex)),
+        theme.success,
+      ),
     ])
   }
 
   if (activeView.value === 'cache') {
-    return usageTooltipContent(palette.value, point.label, [
-      `缓存 Token 占比: ${formatPercent(point.cachedTokenRate)}`,
-      `命中请求率: ${formatPercent(point.cacheHitRequestRate)}`,
+    return usageTooltipContent(theme, point.label, [
+      usageTooltipItem('缓存 Token 占比', formatPercent(point.cachedTokenRate), theme.normal),
+      usageTooltipItem('命中请求率', formatPercent(point.cacheHitRequestRate), theme.success),
     ])
   }
 
   const lines = [
-    `实际费用: ${formatUsd(point.estimatedCost)}`,
+    usageTooltipItem(
+      '实际费用',
+      formatUsd(costAmount(point.estimatedCost, pointIndex)),
+      theme.success,
+    ),
   ]
-  if (point.noCacheCost != null)
-    lines.push(`无缓存费用: ${formatUsd(point.noCacheCost)}`)
-  return usageTooltipContent(palette.value, point.label, lines)
+  if (point.noCacheCost != null) {
+    lines.push(usageTooltipItem(
+      '无缓存费用',
+      formatUsd(costAmount(point.noCacheCost, pointIndex)),
+      theme.textMuted,
+    ))
+  }
+  return usageTooltipContent(theme, point.label, lines)
+}
+
+function costAmount(value: string | null, pointIndex: number) {
+  return value ?? (requestActivity.value[pointIndex] === false ? '0' : null)
 }
 </script>
 
diff --git a/frontend/src/views/usage/components/UsageHealthCard.vue b/frontend/src/views/usage/components/UsageHealthCard.vue
index 228724f7e..6a66fc898 100644
--- a/frontend/src/views/usage/components/UsageHealthCard.vue
+++ b/frontend/src/views/usage/components/UsageHealthCard.vue
@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import type { EChartsOption } from 'echarts'
+import type { BarSeriesOption, EChartsOption, LineSeriesOption } from 'echarts'
 import type { getUsageRecordInsightsOverview } from '@/api'
 import { BarChart } from 'echarts/charts'
 import { use } from 'echarts/core'
@@ -15,9 +15,11 @@ import {
   tooltipIndex,
   tooltipRows,
   usageCategoryAxis,
+  usageGapAwareLineSeries,
   usageLegend,
   usageTooltip,
   usageTooltipContent,
+  usageTooltipItem,
   usageValueAxis,
 } from '../utils/chart'
 import { formatPercent } from '../utils/format'
@@ -60,6 +62,26 @@ const chartOption = computed<EChartsOption>(() => {
   const theme = palette.value
   const chartPoints = points.value
   const activePointCount = chartPoints.filter(point => requestCount(point) > 0).length
+  const successRateSeries = usageGapAwareLineSeries(
+    '服务成功率',
+    chartPoints.map(serviceSuccessRate),
+    theme.success,
+    { yAxisIndex: 1 },
+  )
+  const series: Array<BarSeriesOption | LineSeriesOption> = [
+    outcomeSeries('成功', chartPoints.map(point => point.successRequests), theme.success),
+    outcomeSeries('服务失败', chartPoints.map(point => point.failedRequests), theme.danger),
+    outcomeSeries('取消', chartPoints.map(point => point.cancelledRequests), theme.info),
+    outcomeSeries('未完成', chartPoints.map(point => point.incompleteRequests), theme.warning),
+    outcomeSeries('调用方错误', chartPoints.map(point => point.callerErrorRequests), theme.normal),
+    ...successRateSeries.map((item, index) => index === 0
+      ? {
+          ...item,
+          symbol: activePointCount <= 16 ? 'circle' : 'none',
+          symbolSize: 4,
+        }
+      : item),
+  ]
 
   return {
     animationDuration: 240,
@@ -85,25 +107,7 @@ const chartOption = computed<EChartsOption>(() => {
         splitLine: false,
       }),
     ],
-    series: [
-      outcomeSeries('成功', chartPoints.map(point => point.successRequests), theme.success),
-      outcomeSeries('服务失败', chartPoints.map(point => point.failedRequests), theme.danger),
-      outcomeSeries('取消', chartPoints.map(point => point.cancelledRequests), theme.info),
-      outcomeSeries('未完成', chartPoints.map(point => point.incompleteRequests), theme.warning),
-      outcomeSeries('调用方错误', chartPoints.map(point => point.callerErrorRequests), theme.normal),
-      {
-        name: '服务成功率',
-        type: 'line',
-        yAxisIndex: 1,
-        data: chartPoints.map(serviceSuccessRate),
-        connectNulls: true,
-        smooth: 0.25,
-        symbol: activePointCount <= 16 ? 'circle' : 'none',
-        symbolSize: 4,
-        lineStyle: { color: theme.success, width: 2.2 },
-        itemStyle: { color: theme.success },
-      },
-    ],
+    series,
   }
 })
 
@@ -113,7 +117,9 @@ function requestCount(point: HealthPoint) {
 
 function serviceSuccessRate(point: HealthPoint) {
   const total = Math.max(0, point.successRequests) + Math.max(0, point.failedRequests)
-  return total > 0 ? Math.max(0, point.successRequests ?? 0) / total : null
+  if (total > 0)
+    return Math.max(0, point.successRequests ?? 0) / total
+  return requestCount(point) === 0 ? 0 : null
 }
 
 function outcomeSeries(name: string, data: number[], color: string) {
@@ -134,15 +140,20 @@ function formatTooltip(params: unknown) {
     return ''
 
   const successRate = serviceSuccessRate(point)
+  const theme = palette.value
 
-  return usageTooltipContent(palette.value, point.label, [
-    `请求量: ${formatCompactNumber(requestCount(point))}`,
-    `成功: ${formatCompactNumber(point.successRequests)}`,
-    `服务失败: ${formatCompactNumber(point.failedRequests)}`,
-    `取消: ${formatCompactNumber(point.cancelledRequests)}`,
-    `未完成: ${formatCompactNumber(point.incompleteRequests)}`,
-    `调用方错误: ${formatCompactNumber(point.callerErrorRequests)}`,
-    `服务成功率: ${successRate == null ? '无服务结果' : formatPercent(successRate)}`,
+  return usageTooltipContent(theme, point.label, [
+    usageTooltipItem('请求量', formatCompactNumber(requestCount(point)), theme.textSecondary),
+    usageTooltipItem('成功', formatCompactNumber(point.successRequests), theme.success),
+    usageTooltipItem('服务失败', formatCompactNumber(point.failedRequests), theme.danger),
+    usageTooltipItem('取消', formatCompactNumber(point.cancelledRequests), theme.info),
+    usageTooltipItem('未完成', formatCompactNumber(point.incompleteRequests), theme.warning),
+    usageTooltipItem('调用方错误', formatCompactNumber(point.callerErrorRequests), theme.normal),
+    usageTooltipItem(
+      '服务成功率',
+      successRate == null ? '无服务结果' : formatPercent(successRate),
+      theme.success,
+    ),
   ])
 }
 </script>
diff --git a/frontend/src/views/usage/components/UsageInsightsGrid.vue b/frontend/src/views/usage/components/UsageInsightsGrid.vue
index 0bb0d7633..b2587ab56 100644
--- a/frontend/src/views/usage/components/UsageInsightsGrid.vue
+++ b/frontend/src/views/usage/components/UsageInsightsGrid.vue
@@ -28,7 +28,7 @@ const diagnosticDimension = defineModel('diagnosticDimension', {
 
 <template>
   <section
-    class="mt-5 grid grid-cols-1 gap-3 xl:auto-rows-[24.25rem] xl:grid-cols-2"
+    class="mt-5 grid grid-cols-1 gap-3 xl:auto-rows-97 xl:grid-cols-2"
     aria-label="使用统计观测"
   >
     <UsageHealthCard
@@ -43,8 +43,16 @@ const diagnosticDimension = defineModel('diagnosticDimension', {
       :loading="loading"
     />
 
-    <UsagePerformanceCard :performance="overview.performance" :loading="loading" />
+    <UsagePerformanceCard
+      :performance="overview.performance"
+      :activity="overview.health.points"
+      :loading="loading"
+    />
 
-    <UsageCostCard :cost="overview.cost" :loading="loading" />
+    <UsageCostCard
+      :cost="overview.cost"
+      :activity="overview.health.points"
+      :loading="loading"
+    />
   </section>
 </template>
diff --git a/frontend/src/views/usage/components/UsagePerformanceCard.vue b/frontend/src/views/usage/components/UsagePerformanceCard.vue
index 67fbbc6ac..2c83f81f9 100644
--- a/frontend/src/views/usage/components/UsagePerformanceCard.vue
+++ b/frontend/src/views/usage/components/UsagePerformanceCard.vue
@@ -7,6 +7,7 @@ import BaseCard from '@/components/base/BaseCard.vue'
 import BaseEmpty from '@/components/base/BaseEmpty.vue'
 import BaseSegmented from '@/components/base/BaseSegmented.vue'
 import BaseChart from '@/components/charts/BaseChart.vue'
+import { requestActivityByBucket, zeroInactiveValues } from '@/components/charts/timeSeriesGap'
 import { useChartPalette } from '@/composables/useChartPalette'
 import { formatLocalizedCompactNumber as formatCompactNumber } from '@/utils/number'
 
@@ -14,20 +15,23 @@ import {
   tooltipIndex,
   tooltipRows,
   usageCategoryAxis,
+  usageGapAwareLineSeries,
   usageLegend,
-  usageLineSeries,
   usageTooltip,
   usageTooltipContent,
+  usageTooltipItem,
   usageValueAxis,
 } from '../utils/chart'
 import { formatDuration, formatDurationAxis, formatPercent } from '../utils/format'
 
 type Performance = Awaited<ReturnType<typeof getUsageRecordInsightsOverview>>['performance']
 type PerformancePoint = Performance['points'][number]
+type Activity = Awaited<ReturnType<typeof getUsageRecordInsightsOverview>>['health']['points']
 
 const props = withDefaults(
   defineProps<{
     performance: Performance
+    activity: Activity
     loading?: boolean
   }>(),
   {
@@ -38,6 +42,10 @@ const props = withDefaults(
 const activeView = shallowRef('total')
 const { palette } = useChartPalette()
 const performancePoints = computed<PerformancePoint[]>(() => props.performance.points)
+const requestActivity = computed(() => requestActivityByBucket(
+  performancePoints.value.map(point => point.bucket),
+  props.activity,
+))
 
 const viewOptions = [
   { label: '总耗时', value: 'total' },
@@ -54,14 +62,28 @@ const seriesLabels = computed(() => {
   return ['P50', 'P95', 'P99'] as const
 })
 
-const selectedPoints = computed(() =>
-  performancePoints.value.map(point => ({
+const selectedPoints = computed(() => {
+  const points = performancePoints.value
+  const active = requestActivity.value
+  const firstValues = zeroInactiveValues(
+    points.map(point => seriesValue(point, 'first')),
+    active,
+  )
+  const secondValues = zeroInactiveValues(
+    points.map(point => seriesValue(point, 'second')),
+    active,
+  )
+  const thirdValues = zeroInactiveValues(
+    points.map(point => seriesValue(point, 'third')),
+    active,
+  )
+  return points.map((point, index) => ({
     point,
-    first: seriesValue(point, 'first'),
-    second: seriesValue(point, 'second'),
-    third: seriesValue(point, 'third'),
-  })),
-)
+    first: firstValues[index] ?? null,
+    second: secondValues[index] ?? null,
+    third: thirdValues[index] ?? null,
+  }))
+})
 
 const summaryMetrics = computed(() => {
   const performance = props.performance
@@ -98,6 +120,25 @@ const hasData = computed(
 const chartOption = computed<EChartsOption>(() => {
   const theme = palette.value
   const points = selectedPoints.value
+  const series = [
+    ...usageGapAwareLineSeries(
+      seriesLabels.value[0],
+      points.map(point => point.first),
+      theme.info,
+      { area: 'subtle' },
+    ),
+    ...usageGapAwareLineSeries(
+      seriesLabels.value[1],
+      points.map(point => point.second),
+      theme.warning,
+    ),
+    ...usageGapAwareLineSeries(
+      seriesLabels.value[2],
+      points.map(point => point.third),
+      activeView.value === 'scheduling' ? theme.success : theme.danger,
+      { yAxisIndex: activeView.value === 'scheduling' ? 1 : 0 },
+    ),
+  ]
 
   return {
     animationDuration: 240,
@@ -130,27 +171,7 @@ const chartOption = computed<EChartsOption>(() => {
             ? value => `${formatCompactNumber(value)}/s`
             : formatDurationAxis,
         ),
-    series: [
-      usageLineSeries(
-        seriesLabels.value[0],
-        points.map(point => point.first),
-        theme.info,
-        { area: 'subtle' },
-      ),
-      usageLineSeries(
-        seriesLabels.value[1],
-        points.map(point => point.second),
-        theme.warning,
-      ),
-      {
-        ...usageLineSeries(
-          seriesLabels.value[2],
-          points.map(point => point.third),
-          activeView.value === 'scheduling' ? theme.success : theme.danger,
-        ),
-        yAxisIndex: activeView.value === 'scheduling' ? 1 : 0,
-      },
-    ],
+    series,
   }
 })
 
@@ -180,10 +201,23 @@ function formatTooltip(params: unknown) {
   if (!selected)
     return ''
 
-  return usageTooltipContent(palette.value, selected.point.label, [
-    `${seriesLabels.value[0]}: ${formatSeriesValue(selected.first, 'first')}`,
-    `${seriesLabels.value[1]}: ${formatSeriesValue(selected.second, 'second')}`,
-    `${seriesLabels.value[2]}: ${formatSeriesValue(selected.third, 'third')}`,
+  const theme = palette.value
+  return usageTooltipContent(theme, selected.point.label, [
+    usageTooltipItem(
+      seriesLabels.value[0],
+      formatSeriesValue(selected.first, 'first'),
+      theme.info,
+    ),
+    usageTooltipItem(
+      seriesLabels.value[1],
+      formatSeriesValue(selected.second, 'second'),
+      theme.warning,
+    ),
+    usageTooltipItem(
+      seriesLabels.value[2],
+      formatSeriesValue(selected.third, 'third'),
+      activeView.value === 'scheduling' ? theme.success : theme.danger,
+    ),
   ])
 }
 
diff --git a/frontend/src/views/usage/utils/chart.ts b/frontend/src/views/usage/utils/chart.ts
index a44bac159..36a93316a 100644
--- a/frontend/src/views/usage/utils/chart.ts
+++ b/frontend/src/views/usage/utils/chart.ts
@@ -1,5 +1,6 @@
 import type { LineSeriesOption } from 'echarts'
 import type { useChartPalette } from '@/composables/useChartPalette'
+import { sampleGapBridgeSeries } from '@/components/charts/timeSeriesGap'
 import { chartTooltipStyle } from '@/components/charts/tooltip'
 import { escapeTooltip } from './format'
 
@@ -9,6 +10,8 @@ type UsageAreaStrength = 'strong' | 'subtle'
 interface UsageLineSeriesOptions {
   stack?: string
   area?: UsageAreaStrength | false
+  xAxisIndex?: number
+  yAxisIndex?: number
 }
 
 const areaAlpha: Record<UsageAreaStrength, readonly [string, string]> = {
@@ -36,6 +39,8 @@ export function usageLineSeries(
     data: data.map(value => value ?? null),
     connectNulls: false,
     stack: options.stack,
+    xAxisIndex: options.xAxisIndex ?? 0,
+    yAxisIndex: options.yAxisIndex ?? 0,
     smooth: true,
     showSymbol: showSymbols,
     showAllSymbol: showSymbols,
@@ -61,6 +66,26 @@ export function usageLineSeries(
   }
 }
 
+export function usageGapAwareLineSeries(
+  name: string,
+  data: Array<number | null | undefined>,
+  color: string,
+  options: UsageLineSeriesOptions = {},
+) {
+  const primary = usageLineSeries(name, data, color, options)
+  return [
+    primary,
+    ...sampleGapBridgeSeries(data, {
+      name,
+      color,
+      xAxisIndex: options.xAxisIndex,
+      yAxisIndex: options.yAxisIndex,
+      width: 2.2,
+      z: 2,
+    }),
+  ]
+}
+
 export function usageTooltip(
   theme: UsageChartPalette,
   formatter: (params: unknown) => string,
@@ -81,6 +106,10 @@ export function usageTooltipContent(
   return `<div style="margin:0 0 7px;padding:0 0 7px;border-bottom:1px solid ${theme.divider};color:${theme.textPrimary};font-family:'JetBrains Mono Variable','JetBrains Mono',monospace;font-size:11px;font-weight:750;line-height:1.2">${title}</div><div style="line-height:1.55">${lines.join('<br/>')}</div>`
 }
 
+export function usageTooltipItem(label: string, value: string, color: string) {
+  return `<span style="display:inline-block;width:7px;height:7px;margin-right:6px;border-radius:999px;background:${escapeTooltip(color)}"></span>${escapeTooltip(label)}: ${escapeTooltip(value)}`
+}
+
 export function usageCategoryAxis(labels: string[], theme: UsageChartPalette) {
   return {
     type: 'category' as const,