tracing/histogram: Update document for KEYS_MAX size

Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

kernel os linux

After commit 4f36c2d85ced ("tracing: Increase tracing map KEYS_MAX size"),
'keys' supports up to three fields.

Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Cc: stable@vger.kernel.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20221017103806.2479139-1-zhengyejian1@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

authored by

Zheng Yejian and committed by

Jonathan Corbet 3 years ago a635beea 9abf2313

+1 -1

1 changed file

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Documentation

trace

histogram.rst

+1 -1

Documentation/trace/histogram.rst

··· 39 39 will use the event's kernel stacktrace as the key. The keywords 40 40 'keys' or 'key' can be used to specify keys, and the keywords 41 41 'values', 'vals', or 'val' can be used to specify values. Compound 42 - keys consisting of up to two fields can be specified by the 'keys' 42 + keys consisting of up to three fields can be specified by the 'keys' 43 43 keyword. Hashing a compound key produces a unique entry in the 44 44 table for each unique combination of component keys, and can be 45 45 useful for providing more fine-grained summaries of event data.