false true false LLM_HOST 127.0.0.1 = LLM_PORT 8000 = MODEL gpt-4o = MAX_TOKENS 256 = prompts.csv UTF-8 prompt false , true true false shareMode.all 10 10 true continue 5 false groovy true import groovy.json.JsonOutput import groovy.json.JsonSlurper import java.net.HttpURLConnection // NB: do not import org.apache.jmeter.samplers.SampleResult here — the JSR223 // sampler binds a variable named SampleResult (the current result instance), // and the import would shadow it, breaking calls like SampleResult.latencyEnd(). def host = vars.get("LLM_HOST"); def port = vars.get("LLM_PORT") def body = JsonOutput.toJson([ model: vars.get("MODEL"), stream: true, max_tokens: vars.get("MAX_TOKENS") as int, messages: [[role: "user", content: vars.get("prompt")]] ]) SampleResult.setSampleLabel("POST /v1/chat/completions (stream)") def url = new URL("http://${host}:${port}/v1/chat/completions") HttpURLConnection conn = (HttpURLConnection) url.openConnection() conn.setRequestMethod("POST") conn.setDoOutput(true) conn.setConnectTimeout(5000) conn.setReadTimeout(60000) conn.setRequestProperty("Content-Type", "application/json") conn.setRequestProperty("Accept", "text/event-stream") conn.setRequestProperty("Authorization", "Bearer " + (props.getProperty("llm.api.key") ?: "sk-dummy")) SampleResult.setRequestHeaders(conn.getRequestProperties().toString()) SampleResult.setSamplerData(body) long tSent = System.nanoTime() conn.outputStream.withWriter("UTF-8") { it << body } int status = conn.responseCode def slurper = new JsonSlurper() def text = new StringBuilder() int tokens = 0 long tFirst = 0L, tPrev = 0L def gaps = [] conn.inputStream.withReader("UTF-8") { reader -> String line while ((line = reader.readLine()) != null) { if (!line.startsWith("data:")) continue def payload = line.substring(5).trim() if (payload == "[DONE]") break long now = System.nanoTime() if (tFirst == 0L) { tFirst = now; SampleResult.latencyEnd() } def delta = slurper.parseText(payload)?.choices?.getAt(0)?.delta?.content if (delta) { tokens++ text << delta if (tPrev != 0L) gaps << (now - tPrev) / 1_000_000d tPrev = now } } } long tLast = System.nanoTime() double ttftMs = tFirst ? (tFirst - tSent) / 1_000_000d : -1 double totalMs = (tLast - tSent) / 1_000_000d double genMs = tFirst ? (tLast - tFirst) / 1_000_000d : 0 double tps = genMs > 0 ? tokens / (genMs / 1000d) : 0 double itlP50 = gaps ? gaps.sort()[(int) (gaps.size() * 0.5)] : 0 SampleResult.setResponseCode(status.toString()) SampleResult.setResponseData(text.toString(), "UTF-8") SampleResult.setResponseHeaders("ttft_ms=${ttftMs.round(1)}\ntokens=${tokens}\ntokens_per_sec=${tps.round(1)}\nitl_p50_ms=${itlP50.round(1)}") SampleResult.setSuccessful(status == 200 && tokens > 0) if (!SampleResult.isSuccessful()) SampleResult.setResponseMessage("HTTP ${status}, tokens=${tokens}") vars.put("ttft_ms", ttftMs.round(1).toString()) vars.put("tokens", tokens.toString()) vars.put("tokens_per_sec", tps.round(1).toString()) vars.put("itl_p50_ms", itlP50.round(1).toString()) vars.put("total_ms", totalMs.round(1).toString()) log.info("TTFT=${ttftMs.round(1)}ms tokens=${tokens} tok/s=${tps.round(1)} ITL p50=${itlP50.round(1)}ms total=${totalMs.round(1)}ms") 200 Assertion.response_code false 8 groovy true File f = new File("results/llm-metrics.csv") f.getParentFile().mkdirs() synchronized (f) { if (!f.exists()) { f.append("timestamp,thread,ttft_ms,tokens,tokens_per_sec,itl_p50_ms,total_ms\n") } f.append("${prev.getEndTime()},${prev.getThreadName()},${vars.get('ttft_ms')},${vars.get('tokens')},${vars.get('tokens_per_sec')},${vars.get('itl_p50_ms')},${vars.get('total_ms')}\n") } false saveConfig true true true true true true true true true false true true false false false true false false false true 0 true true true true true true false saveConfig true true true true true true true true true false true true false false false true false false false true 0 true true true true true true false saveConfig true true true true true true true true true false true true false false false true false false false true 0 true true true true true true false saveConfig true true true true true true true true true false true true false false false true false false false true 0 true true true true true true results/results.jtl