openssl/doc/man3/OPENSSL_LH_stats.pod
Pauli 2e8b5d75af Document that lhash isn't thread safe under any circumstances and
indicate the level of locking required for various operations.

Remove the lock and atomics from the lhash code.  These we're not complete
or adequate.

Refer to #4418 and #4427 for details.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4429)
2017-10-09 07:50:18 +10:00

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=pod
=head1 NAME
OPENSSL_LH_stats, OPENSSL_LH_node_stats, OPENSSL_LH_node_usage_stats,
OPENSSL_LH_stats_bio,
OPENSSL_LH_node_stats_bio, OPENSSL_LH_node_usage_stats_bio - LHASH statistics
=head1 SYNOPSIS
#include <openssl/lhash.h>
void OPENSSL_LH_stats(LHASH *table, FILE *out);
void OPENSSL_LH_node_stats(LHASH *table, FILE *out);
void OPENSSL_LH_node_usage_stats(LHASH *table, FILE *out);
void OPENSSL_LH_stats_bio(LHASH *table, BIO *out);
void OPENSSL_LH_node_stats_bio(LHASH *table, BIO *out);
void OPENSSL_LH_node_usage_stats_bio(LHASH *table, BIO *out);
=head1 DESCRIPTION
The B<LHASH> structure records statistics about most aspects of
accessing the hash table.
OPENSSL_LH_stats() prints out statistics on the size of the hash table, how
many entries are in it, and the number and result of calls to the
routines in this library.
OPENSSL_LH_node_stats() prints the number of entries for each 'bucket' in the
hash table.
OPENSSL_LH_node_usage_stats() prints out a short summary of the state of the
hash table. It prints the 'load' and the 'actual load'. The load is
the average number of data items per 'bucket' in the hash table. The
'actual load' is the average number of items per 'bucket', but only
for buckets which contain entries. So the 'actual load' is the
average number of searches that will need to find an item in the hash
table, while the 'load' is the average number that will be done to
record a miss.
OPENSSL_LH_stats_bio(), OPENSSL_LH_node_stats_bio() and OPENSSL_LH_node_usage_stats_bio()
are the same as the above, except that the output goes to a B<BIO>.
=head1 RETURN VALUES
These functions do not return values.
=head1 NOTE
These calls should be made under a read lock. Refer to
L<OPENSSL_LH_COMPFUNC(3)/NOTE> for more details about the locks required
when using the LHASH data structure.
=head1 SEE ALSO
L<bio(7)>, L<OPENSSL_LH_COMPFUNC(3)>
=head1 COPYRIGHT
Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut