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| author | Beau Belgrave <beaub@linux.microsoft.com> | 2022-07-29 02:33:08 +0300 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-09-29 17:17:37 +0300 |
| commit | 39d6d08b2edf99c4b39a689a70bf0adee065b357 (patch) | |
| tree | 2dfb47d9ea7e51415af2cd79815f2c9597786655 /include/linux/user_events.h | |
| parent | d401b72458562c2f2a81dad162de5c1b8e191e17 (diff) | |
| download | linux-39d6d08b2edf99c4b39a689a70bf0adee065b357.tar.xz | |
tracing/user_events: Use bits vs bytes for enabled status page data
User processes may require many events and when they do the cache
performance of a byte index status check is less ideal than a bit index.
The previous event limit per-page was 4096, the new limit is 32,768.
This change adds a bitwise index to the user_reg struct. Programs check
that the bit at status_bit has a bit set within the status page(s).
Link: https://lkml.kernel.org/r/20220728233309.1896-6-beaub@linux.microsoft.com
Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/user_events.h')
| -rw-r--r-- | include/linux/user_events.h | 15 |
1 files changed, 3 insertions, 12 deletions
diff --git a/include/linux/user_events.h b/include/linux/user_events.h index 736e05603463..592a3fbed98e 100644 --- a/include/linux/user_events.h +++ b/include/linux/user_events.h @@ -20,15 +20,6 @@ #define USER_EVENTS_SYSTEM "user_events" #define USER_EVENTS_PREFIX "u:" -/* Bits 0-6 are for known probe types, Bit 7 is for unknown probes */ -#define EVENT_BIT_FTRACE 0 -#define EVENT_BIT_PERF 1 -#define EVENT_BIT_OTHER 7 - -#define EVENT_STATUS_FTRACE (1 << EVENT_BIT_FTRACE) -#define EVENT_STATUS_PERF (1 << EVENT_BIT_PERF) -#define EVENT_STATUS_OTHER (1 << EVENT_BIT_OTHER) - /* Create dynamic location entry within a 32-bit value */ #define DYN_LOC(offset, size) ((size) << 16 | (offset)) @@ -45,12 +36,12 @@ struct user_reg { /* Input: Pointer to string with event name, description and flags */ __u64 name_args; - /* Output: Byte index of the event within the status page */ - __u32 status_index; + /* Output: Bitwise index of the event within the status page */ + __u32 status_bit; /* Output: Index of the event to use when writing data */ __u32 write_index; -}; +} __attribute__((__packed__)); #define DIAG_IOC_MAGIC '*' |