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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "CameraLatencyHistogram"
     18 #include <inttypes.h>
     19 #include <utils/Log.h>
     20 #include <utils/String8.h>
     21 
     22 #include "LatencyHistogram.h"
     23 
     24 namespace android {
     25 
     26 CameraLatencyHistogram::CameraLatencyHistogram(int32_t binSizeMs, int32_t binCount) :
     27         mBinSizeMs(binSizeMs),
     28         mBinCount(binCount),
     29         mBins(binCount),
     30         mTotalCount(0) {
     31 }
     32 
     33 void CameraLatencyHistogram::add(nsecs_t start, nsecs_t end) {
     34     nsecs_t duration = end - start;
     35     int32_t durationMs = static_cast<int32_t>(duration / 1000000LL);
     36     int32_t binIndex = durationMs / mBinSizeMs;
     37 
     38     if (binIndex < 0) {
     39         binIndex = 0;
     40     } else if (binIndex >= mBinCount) {
     41         binIndex = mBinCount-1;
     42     }
     43 
     44     mBins[binIndex]++;
     45     mTotalCount++;
     46 }
     47 
     48 void CameraLatencyHistogram::reset() {
     49     mBins.clear();
     50     mTotalCount = 0;
     51 }
     52 
     53 void CameraLatencyHistogram::dump(int fd, const char* name) const {
     54     if (mTotalCount == 0) {
     55         return;
     56     }
     57 
     58     String8 lines;
     59     lines.appendFormat("%s (%" PRId64 ") samples\n", name, mTotalCount);
     60 
     61     String8 lineBins, lineBinCounts;
     62     formatHistogramText(lineBins, lineBinCounts);
     63 
     64     lineBins.append("\n");
     65     lineBinCounts.append("\n");
     66     lines.append(lineBins);
     67     lines.append(lineBinCounts);
     68 
     69     write(fd, lines.string(), lines.size());
     70 }
     71 
     72 void CameraLatencyHistogram::log(const char* fmt, ...) {
     73     if (mTotalCount == 0) {
     74         return;
     75     }
     76 
     77     va_list args;
     78     va_start(args, fmt);
     79     String8 histogramName = String8::formatV(fmt, args);
     80     ALOGI("%s (%" PRId64 ") samples:", histogramName.string(), mTotalCount);
     81     va_end(args);
     82 
     83     String8 lineBins, lineBinCounts;
     84     formatHistogramText(lineBins, lineBinCounts);
     85 
     86     ALOGI("%s", lineBins.c_str());
     87     ALOGI("%s", lineBinCounts.c_str());
     88 }
     89 
     90 void CameraLatencyHistogram::formatHistogramText(
     91         String8& lineBins, String8& lineBinCounts) const {
     92     lineBins = "  ";
     93     lineBinCounts = "  ";
     94 
     95     for (int32_t i = 0; i < mBinCount; i++) {
     96         if (i == mBinCount - 1) {
     97             lineBins.append("    inf (max ms)");
     98         } else {
     99             lineBins.appendFormat("%7d", mBinSizeMs*(i+1));
    100         }
    101         lineBinCounts.appendFormat("   %02.2f", 100.0*mBins[i]/mTotalCount);
    102     }
    103     lineBinCounts.append(" (%)");
    104 }
    105 
    106 }; //namespace android
    107