# criterion performance measurements

## overview

want to understand this report?

## Word32/printf

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 1.536981570043631e-6 | 1.5514655581167907e-6 | 1.5886010572307786e-6 |

Standard deviation | 3.810078560158444e-8 | 6.774124480538762e-8 | 1.259785482509006e-7 |

Outlying measurements have severe (0.5891603348512913%) effect on estimated standard deviation.

## Word32/showHex

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 1.2760109915902572e-7 | 1.2853724573609164e-7 | 1.2967737033771725e-7 |

Standard deviation | 2.7841290137645084e-9 | 3.780478873064417e-9 | 4.8329185706619764e-9 |

Outlying measurements have moderate (0.44718215753059226%) effect on estimated standard deviation.

## Word32/xbuild

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 3.282780208074934e-7 | 3.411793596896122e-7 | 3.663549395982028e-7 |

Standard deviation | 3.477511918468043e-8 | 5.2955855579933917e-8 | 7.176604900757127e-8 |

Outlying measurements have severe (0.9589758958231043%) effect on estimated standard deviation.

## Word32/xbuildu

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 3.9676427515399716e-7 | 4.0783377014950056e-7 | 4.2193065718260677e-7 |

Standard deviation | 2.6526903919912055e-8 | 4.220099889326817e-8 | 6.16294105836812e-8 |

Outlying measurements have severe (0.903456632891851%) effect on estimated standard deviation.

## Word32/xshowl

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 4.7384212182640497e-7 | 4.786413519439609e-7 | 4.848746249354143e-7 |

Standard deviation | 1.246117586139819e-8 | 1.6892409532132195e-8 | 2.310770280621286e-8 |

Outlying measurements have severe (0.5111591246934704%) effect on estimated standard deviation.

## Word32/xshowlp

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 5.162387815144622e-7 | 5.259252162596607e-7 | 5.37385285014246e-7 |

Standard deviation | 2.619207153081674e-8 | 3.332279647291653e-8 | 4.307148364000975e-8 |

Outlying measurements have severe (0.7706448412074517%) effect on estimated standard deviation.

## Word32/xshowlu

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 5.980486724429498e-7 | 6.093298923319493e-7 | 6.278415321474831e-7 |

Standard deviation | 3.2089229883353357e-8 | 4.834637114491929e-8 | 7.621744512222333e-8 |

Outlying measurements have severe (0.8432480513842034%) effect on estimated standard deviation.

## Word32/xshowlpu

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 5.927387559523927e-7 | 6.020710047542299e-7 | 6.173146968693954e-7 |

Standard deviation | 2.2613298823506995e-8 | 3.685595378263953e-8 | 5.777811585599681e-8 |

Outlying measurements have severe (0.7591264669360107%) effect on estimated standard deviation.

## Word32/xshow

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 5.038082721968536e-7 | 5.147912760664756e-7 | 5.371449813479116e-7 |

Standard deviation | 2.418232047939545e-8 | 4.8574774667003966e-8 | 1.0603348425722795e-7 |

Outlying measurements have severe (0.882726157614506%) effect on estimated standard deviation.

## Word32/xshowp

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 5.398751322078301e-7 | 5.457994315842402e-7 | 5.591650843188845e-7 |

Standard deviation | 1.679881828507219e-8 | 2.816563630296205e-8 | 5.0254548152647034e-8 |

Outlying measurements have severe (0.6880251164700695%) effect on estimated standard deviation.

## Word32/xshowu

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 5.7570566645222e-7 | 5.802058691290143e-7 | 5.871563269594317e-7 |

Standard deviation | 1.0848794885812115e-8 | 1.8456129337286982e-8 | 2.922310141141794e-8 |

Outlying measurements have moderate (0.45320297785362906%) effect on estimated standard deviation.

## Word32/xshowpu

lower bound | estimate | upper bound | |
---|---|---|---|

OLS regression | xxx | xxx | xxx |

R² goodness-of-fit | xxx | xxx | xxx |

Mean execution time | 6.253283322651222e-7 | 6.357214633587154e-7 | 6.532380868058045e-7 |

Standard deviation | 2.3979522909402098e-8 | 4.718727343830783e-8 | 8.821967132758944e-8 |

Outlying measurements have severe (0.8236838397896818%) effect on estimated standard deviation.

## understanding this report

In this report, each function benchmarked by criterion is assigned a section of its own. The charts in each section are active; if you hover your mouse over data points and annotations, you will see more details.

- The chart on the left is a kernel density estimate (also known as a KDE) of time measurements. This graphs the probability of any given time measurement occurring. A spike indicates that a measurement of a particular time occurred; its height indicates how often that measurement was repeated.
- The chart on the right is the raw data from which the kernel
density estimate is built. The
*x*axis indicates the number of loop iterations, while the*y*axis shows measured execution time for the given number of loop iterations. The line behind the values is the linear regression prediction of execution time for a given number of iterations. Ideally, all measurements will be on (or very near) this line.

Under the charts is a small table. The first two rows are the results of a linear regression run on the measurements displayed in the right-hand chart.

*OLS regression*indicates the time estimated for a single loop iteration using an ordinary least-squares regression model. This number is more accurate than the*mean*estimate below it, as it more effectively eliminates measurement overhead and other constant factors.*R² goodness-of-fit*is a measure of how accurately the linear regression model fits the observed measurements. If the measurements are not too noisy, R² should lie between 0.99 and 1, indicating an excellent fit. If the number is below 0.99, something is confounding the accuracy of the linear model.*Mean execution time*and*standard deviation*are statistics calculated from execution time divided by number of iterations.

We use a statistical technique called the bootstrap to provide confidence intervals on our estimates. The bootstrap-derived upper and lower bounds on estimates let you see how accurate we believe those estimates to be. (Hover the mouse over the table headers to see the confidence levels.)

A noisy benchmarking environment can cause some or many measurements to fall far from the mean. These outlying measurements can have a significant inflationary effect on the estimate of the standard deviation. We calculate and display an estimate of the extent to which the standard deviation has been inflated by outliers.