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| author | Nick Alcock <nick.alcock@oracle.com> | 2020-06-02 21:00:35 +0100 |
|---|---|---|
| committer | Nick Alcock <nick.alcock@oracle.com> | 2020-07-22 17:57:34 +0100 |
| commit | 5ec7465fec8bceb477732d6757112fe162116eb8 (patch) | |
| tree | 53501c491c9e75c45e70d2e80c51f6ee1662b609 | |
| parent | 601e455b758b7075d3027c030b9bd60f7b7face5 (diff) | |
| download | gdb-5ec7465fec8bceb477732d6757112fe162116eb8.zip gdb-5ec7465fec8bceb477732d6757112fe162116eb8.tar.gz gdb-5ec7465fec8bceb477732d6757112fe162116eb8.tar.bz2 | |
libctf: having debugging enabled is unlikely
The deduplicator can emit enormous amounts of debugging output,
so much so that a later commit will introduce a new configure flag
that configures most of it out (and configures it out by default).
It became clear that when this configure flag is on, but debugging is
not enabled via the LIBCTF_DEBUG environment variable, up to 10% of
runtime can be spent on branch mispredictions checking the _libctf_debug
variable. Mark it unlikely to be set (when it is set, performance is
likely to be the least of your concerns).
libctf/
* ctf-subr.c (ctf_dprintf): _libctf_debug is unlikely to be set.
| -rw-r--r-- | libctf/ChangeLog | 4 | ||||
| -rw-r--r-- | libctf/ctf-subr.c | 2 |
2 files changed, 5 insertions, 1 deletions
diff --git a/libctf/ChangeLog b/libctf/ChangeLog index da28502..4879804 100644 --- a/libctf/ChangeLog +++ b/libctf/ChangeLog @@ -1,5 +1,9 @@ 2020-07-22 Nick Alcock <nick.alcock@oracle.com> + * ctf-subr.c (ctf_dprintf): _libctf_debug is unlikely to be set. + +2020-07-22 Nick Alcock <nick.alcock@oracle.com> + * ctf-impl.h (struct ctf_archive_internal) <ctfi_unmap_on_close>: New. (ctf_new_archive_internal): Adjust. diff --git a/libctf/ctf-subr.c b/libctf/ctf-subr.c index 114df84..a5cde9d 100644 --- a/libctf/ctf-subr.c +++ b/libctf/ctf-subr.c @@ -183,7 +183,7 @@ int ctf_getdebug (void) _libctf_printflike_ (1, 2) void ctf_dprintf (const char *format, ...) { - if (_libctf_debug) + if (_libctf_unlikely_ (_libctf_debug)) { va_list alist; |