server_latency.Rmd

---
title: "server_latency"
author: "Gregory Jefferis"
date: "29 November 2016"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r}
calls=readLines("sample_fafb_curl_calls.sh")

```

```{r}
time_call <- function(u) {
  newcall=sub("curl", 'curl -s -w "%{time_total}\n" -o /dev/null', u)
  as.numeric(system(newcall, intern=T))
}

```

```{r}
time_call(calls[1])
```

Now let's pick 100 calls at random. But not all are jpegs, so let's use those:

```{r}
table(grepl("jpg",calls))
jpgs=grep("jpg",calls, value = T)
```

OK, so 100 calls at random

```{r}
set.seed(42)
call_times=sapply(sample(jpgs, 100), time_call)
```


```{r}
hist(call_times)
```