.. _h2load-1-output:

OUTPUT
------

REQUEST METRICS
~~~~~~~~~~~~~~~

requests
  total
    The total number of requests h2load was instructed to make.
  started
    The number of requests initiated by the tool.
  done
    The number of requests that reached completion.
  succeeded
    Requests resulting in an HTTP 2xx or 3xx status code.
  failed
    The total number of failed requests.  This includes both
    ``errored`` requests and requests that completed with a
    non-2xx/3xx status code.
  errored
    A subset of ``failed`` where the requests failed due to
    network-level issues (e.g., TCP resets, ``RST_STREAM``) rather
    than HTTP status codes.
  timeout
    A subset of ``errored`` where the connection timed out before
    completion.

status codes
  The specific count of received HTTP status codes categorized by
  class (2xx, 3xx, 4xx, 5xx).

TRAFFIC METRICS
~~~~~~~~~~~~~~~

traffic
  total
    Total application data bytes received "on the wire" (decrypted if
    using TLS).
  headers
    Total bytes used for response headers (pre-decompression).

    space savings
      Header compression efficiency, calculated as:

      (1 - headers / decompressed_headers) * 100

      where ``headers`` is the compressed size and
      ``decompressed_headers`` is the size after decompression.
  data
    Total bytes received in response bodies.

PERFORMANCE STATISTICS
~~~~~~~~~~~~~~~~~~~~~~

Metric Definitions
  request
    The duration from sending the first byte of a request to receiving
    the last byte of the response.
  connect
    The time taken to establish a connection, including TLS
    handshakes.
  TTFB
    The duration until the first byte of application data is received
    from the server (decrypted if using TLS).
  req/s
    The requests per second measured individually across all clients.
  min RTT
    The minimum RTT (QUIC).
  smoothed RTT
    The smoothed RTT (QUIC).
  packets sent
    The number of packets sent (QUIC).
  packets recv
    The number of packets received (QUIC).
  packets lost
    The number of packets declared lost (QUIC).
  GRO packets
    The number of packets received in a single recvmsg call (QUIC).

Distribution Fields
  min / max
    The absolute minimum and maximum values recorded.
  median
    The 50th percentile value.
  p95 / p99
    The 95th and 99th percentiles, indicating tail performance.
  mean
    The arithmetic average of all samples.
  sd
    The standard deviation (measure of data dispersion).
  +/- sd
    The percentage of successful samples falling within one standard
    deviation of the mean (mean +/- sd).

FLOW CONTROL
------------

h2load sets large flow control window by default, and effectively
disables flow control to avoid under utilization of server
performance.  To set smaller flow control window, use :option:`-w` and
:option:`-W` options.  For example, use ``-w16 -W16`` to set default
window size described in HTTP/2 protocol specification.

SEE ALSO
--------

:manpage:`nghttp(1)`, :manpage:`nghttpd(1)`, :manpage:`nghttpx(1)`
