GSP
Quick Navigator
Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
H2LOAD(1) nghttp2 H2LOAD(1)

h2load - HTTP/2 benchmarking tool

h2load [OPTIONS]... [URI]...

benchmarking tool for HTTP/2 server

<URI>
Specify URI to access. Multiple URIs can be specified. URIs are used in this order for each client. All URIs are used, then first URI is used and then 2nd URI, and so on. The scheme, host and port in the subsequent URIs, if present, are ignored. Those in the first URI are used solely. Definition of a base URI overrides all scheme, host or port values.

Number of requests across all clients. If it is used with --timing-script-file option, this option specifies the number of requests each client performs rather than the number of requests across all clients. This option is ignored if timing-based benchmarking is enabled (see --duration option).

Default: 1


Number of concurrent clients. With -r option, this specifies the maximum number of connections to be made.

Default: 1


Number of native threads.

Default: 1


Path of a file with multiple URIs are separated by EOLs. This option will disable URIs getting from command-line. If '-' is given as <PATH>, URIs will be read from stdin. URIs are used in this order for each client. All URIs are used, then first URI is used and then 2nd URI, and so on. The scheme, host and port in the subsequent URIs, if present, are ignored. Those in the first URI are used solely. Definition of a base URI overrides all scheme, host or port values.

Max concurrent streams to issue per session. When http/1.1 is used, this specifies the number of HTTP pipelining requests in-flight.

Default: 1


Maximum frame size that the local endpoint is willing to receive.

Default: 16K


Sets the stream level initial window size to (2**<N>)-1. For QUIC, <N> is capped to 26 (roughly 64MiB).

Default: 30


Sets the connection level initial window size to (2**<N>)-1.

Default: 30


Add/Override a header to the requests.

Set allowed cipher list for TLSv1.2 or earlier. The format of the string is described in OpenSSL ciphers(1).

Default: ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384


Set allowed cipher list for TLSv1.3. The format of the string is described in OpenSSL ciphers(1).

Default: TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_CCM_SHA256


Specify ALPN identifier of the protocol to be used when accessing http URI without SSL/TLS. Available protocols: h2c and http/1.1

Default: h2c


Post FILE to server. The request method is changed to POST. For http/1.1 connection, if -d is used, the maximum number of in-flight pipelined requests is set to 1.

Specifies the fixed rate at which connections are created. The rate must be a positive integer, representing the number of connections to be made per rate period. The maximum number of connections to be made is given in -c option. This rate will be distributed among threads as evenly as possible. For example, with -t2 and -r4, each thread gets 2 connections per period. When the rate is 0, the program will run as it normally does, creating connections at whatever variable rate it wants. The default value for this option is 0. -r and -D are mutually exclusive.

Specifies the time period between creating connections. The period must be a positive number, representing the length of the period in time. This option is ignored if the rate option is not used. The default value for this option is 1s.

Specifies the main duration for the measurements in case of timing-based benchmarking. -D and -r are mutually exclusive.

Specifies the time period before starting the actual measurements, in case of timing-based benchmarking. Needs to provided along with -D option.

Specifies the maximum time that h2load is willing to keep a connection open, regardless of the activity on said connection. <DURATION> must be a positive integer, specifying the amount of time to wait. When no timeout value is set (either active or inactive), h2load will keep a connection open indefinitely, waiting for a response.

Specifies the amount of time that h2load is willing to wait to see activity on a given connection. <DURATION> must be a positive integer, specifying the amount of time to wait. When no timeout value is set (either active or inactive), h2load will keep a connection open indefinitely, waiting for a response.

Path of a file containing one or more lines separated by EOLs. Each script line is composed of two tab-separated fields. The first field represents the time offset from the start of execution, expressed as a positive value of milliseconds with microsecond resolution. The second field represents the URI. This option will disable URIs getting from command-line. If '-' is given as <PATH>, script lines will be read from stdin. Script lines are used in order for each client. If -n is given, it must be less than or equal to the number of script lines, larger values are clamped to the number of script lines. If -n is not given, the number of requests will default to the number of script lines. The scheme, host and port defined in the first URI are used solely. Values contained in other URIs, if present, are ignored. Definition of a base URI overrides all scheme, host or port values. --timing-script-file and --rps are mutually exclusive.

Specify URI from which the scheme, host and port will be used for all requests. The base URI overrides all values defined either at the command line or inside input files. If argument starts with "unix:", then the rest of the argument will be treated as UNIX domain socket path. The connection is made through that path instead of TCP. In this case, scheme is inferred from the first URI appeared in the command line or inside input files as usual.

Comma delimited list of ALPN protocol identifier sorted in the order of preference. That means most desirable protocol comes first. The parameter must be delimited by a single comma only and any white spaces are treated as a part of protocol string.

Default: h2,http/1.1


Short hand for --alpn-list=http/1.1 --no-tls-proto=http/1.1, which effectively force http/1.1 for both http and https URI.

Specify decoder header table size.

Default: 4K


Specify encoder header table size. The decoder (server) specifies the maximum dynamic table size it accepts. Then the negotiated dynamic table size is the minimum of this option value and the value which server specified.

Default: 4K


Write per-request information to a file as tab-separated columns: start time as microseconds since epoch; HTTP status code; microseconds until end of response. More columns may be added later. Rows are ordered by end-of- response time when using one worker thread, but may appear slightly out of order with multiple threads due to buffering. Status code is -1 for failed streams.

Enable qlog output and specify base file name for qlogs. Qlog is emitted for each connection. For a given base name "base", each output file name becomes "base.M.N.sqlog" where M is worker ID and N is client ID (e.g. "base.0.3.sqlog"). Only effective in QUIC runs.

Host and port to connect instead of using the authority in <URI>.

Specify request per second for each client. --rps and --timing-script-file are mutually exclusive.

Specify the supported groups.

Default: X25519:P-256:P-384:P-521


Disable UDP GSO.

--max-udp-payload-size=<SIZE>
Specify the maximum outgoing UDP datagram payload size.

Enable ktls.

Send <DNSNAME> in TLS SNI, overriding the host name specified in URI.

Output debug information.

Display version information and exit.

Display this help and exit.

The <SIZE> argument is an integer and an optional unit (e.g., 10K is 10 * 1024). Units are K, M and G (powers of 1024).

The <DURATION> argument is an integer and an optional unit (e.g., 1s is 1 second and 500ms is 500 milliseconds). Units are h, m, s or ms (hours, minutes, seconds and milliseconds, respectively). If a unit is omitted, a second is used as unit.

The number of requests h2load was instructed to make.
The number of requests h2load has started.
The number of requests completed.
The number of requests completed successfully. Only HTTP status code 2xx or3xx are considered as success.
The number of requests failed, including HTTP level failures (non-successful HTTP status code).
The number of requests failed, except for HTTP level failures. This is the subset of the number reported in failed and most likely the network level failures or stream was reset by RST_STREAM.
The number of requests whose connection timed out before they were completed. This is the subset of the number reported in errored.

The number of status code h2load received.
The number of bytes received from the server "on the wire". If requests were made via TLS, this value is the number of decrypted bytes.
The number of response header bytes from the server without decompression. The space savings shows efficiency of header compression. Let decompressed(headers) to the number of bytes used for header fields after decompression. The space savings is calculated by (1 - headers / decompressed(headers)) * 100. For HTTP/1.1, this is usually 0.00%, since it does not have header compression. For HTTP/2, it shows some insightful numbers.
The number of response body bytes received from the server.

The minimum time taken for request and response.
The maximum time taken for request and response.
The mean time taken for request and response.
The standard deviation of the time taken for request and response.
+/- sd
The fraction of the number of requests within standard deviation range (mean +/- sd) against total number of successful requests.

The minimum time taken to connect to a server including TLS handshake.
The maximum time taken to connect to a server including TLS handshake.
The mean time taken to connect to a server including TLS handshake.
The standard deviation of the time taken to connect to a server.
+/- sd
The fraction of the number of connections within standard deviation range (mean +/- sd) against total number of successful connections.

The minimum time taken to get 1st byte from a server.
The maximum time taken to get 1st byte from a server.
The mean time taken to get 1st byte from a server.
The standard deviation of the time taken to get 1st byte from a server.
+/- sd
The fraction of the number of connections within standard deviation range (mean +/- sd) against total number of successful connections.

The minimum request per second among all clients.
The maximum request per second among all clients.
The mean request per second among all clients.
The standard deviation of request per second among all clients. server.
+/- sd
The fraction of the number of connections within standard deviation range (mean +/- sd) against total number of successful connections.


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 -w and -W options. For example, use -w16 -W16 to set default window size described in HTTP/2 protocol specification.

nghttp(1), nghttpd(1), nghttpx(1)

Tatsuhiro Tsujikawa

2012, 2015, 2016, Tatsuhiro Tsujikawa

June 17, 2025 1.66.0
Search for    or go to Top of page |  Section 1 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.