const logger = require('@overleaf/logger') const Metrics = require('./Metrics') const os = require('os') let CACHED_LOAD = { expires: -1, load: [0, 0, 0], } function getSystemLoad() { if (CACHED_LOAD.expires < Date.now()) { CACHED_LOAD = { expires: Date.now() + 10 * 1000, load: os.loadavg(), } } return CACHED_LOAD.load } const ONE_MB = 1024 * 1024 function emitPdfStats(stats, timings, request) { if (timings['compute-pdf-caching']) { emitPdfCachingStats(stats, timings, request) } else { // How much bandwidth will the pdf incur when downloaded in full? Metrics.summary('pdf-bandwidth', stats['pdf-size'], request.metricsOpts) } } function emitPdfCachingStats(stats, timings, request) { if (!stats['pdf-size']) return // double check // How much extra time did we spent in PDF.js? Metrics.timing( 'compute-pdf-caching', timings['compute-pdf-caching'], 1, request.metricsOpts ) // How large is the overhead of hashing up-front? const fraction = timings.compileE2E - timings['compute-pdf-caching'] !== 0 ? timings.compileE2E / (timings.compileE2E - timings['compute-pdf-caching']) : 1 if (fraction > 1.5 && timings.compileE2E > 10 * 1000) { logger.warn( { stats, timings, load: getSystemLoad(), }, 'slow pdf caching' ) } Metrics.summary( 'overhead-compute-pdf-ranges', fraction * 100 - 100, request.metricsOpts ) // How does the hashing scale to pdf size in MB? Metrics.timing( 'compute-pdf-caching-relative-to-pdf-size', timings['compute-pdf-caching'] / (stats['pdf-size'] / ONE_MB), 1, request.metricsOpts ) if (stats['pdf-caching-total-ranges-size']) { // How does the hashing scale to total ranges size in MB? Metrics.timing( 'compute-pdf-caching-relative-to-total-ranges-size', timings['compute-pdf-caching'] / (stats['pdf-caching-total-ranges-size'] / ONE_MB), 1, request.metricsOpts ) // How fast is the hashing per range on average? Metrics.timing( 'compute-pdf-caching-relative-to-ranges-count', timings['compute-pdf-caching'] / stats['pdf-caching-n-ranges'], 1, request.metricsOpts ) // How many ranges are new? Metrics.summary( 'new-pdf-ranges-relative-to-total-ranges', (stats['pdf-caching-n-new-ranges'] / stats['pdf-caching-n-ranges']) * 100, request.metricsOpts ) } // How much content is cacheable? Metrics.summary( 'cacheable-ranges-to-pdf-size', (stats['pdf-caching-total-ranges-size'] / stats['pdf-size']) * 100, request.metricsOpts ) const sizeWhenDownloadedInFull = // All of the pdf stats['pdf-size'] - // These ranges are potentially cached. stats['pdf-caching-total-ranges-size'] + // These ranges are not cached. stats['pdf-caching-new-ranges-size'] // How much bandwidth can we save when downloading the pdf in full? Metrics.summary( 'pdf-bandwidth-savings', 100 - (sizeWhenDownloadedInFull / stats['pdf-size']) * 100, request.metricsOpts ) // How much bandwidth will the pdf incur when downloaded in full? Metrics.summary( 'pdf-bandwidth', sizeWhenDownloadedInFull, request.metricsOpts ) // How much space do the ranges use? // This will accumulate the ranges size over time, skipping already written ranges. Metrics.summary( 'pdf-ranges-disk-size', stats['pdf-caching-new-ranges-size'] - stats['pdf-caching-reclaimed-space'], request.metricsOpts ) } module.exports = { emitPdfStats, }