X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvppinfra%2Fmaplog.h;h=ea6a835c7b5bf7a6db7caaa98c35a21e05926af6;hb=8c8acc0;hp=192dc22a71b4ec6fd24916025bef72423620ab31;hpb=e9d9170b5546c3c5e768ba3ed26a525a16501c6e;p=vpp.git diff --git a/src/vppinfra/maplog.h b/src/vppinfra/maplog.h index 192dc22a71b..ea6a835c7b5 100644 --- a/src/vppinfra/maplog.h +++ b/src/vppinfra/maplog.h @@ -16,9 +16,17 @@ #ifndef __included_maplog_h__ #define __included_maplog_h__ -/** \file +/** @file + @brief mmap-based thread-safe fixed-size record double-buffered logging. - mmap-based fixed-size record double-buffered logging + This scheme should be about as fast as practicable. By fiat, log + records are rounded to a multiple of CLIB_CACHE_LINE_BYTES. + Consumer code calls clib_maplog_get_entry(...) to obtain a pointer + to a log entry. + + We use an atomic ticket-counter to dole out log entries. Whichever + client thread crosses the double-buffer boundary is in charge of + replacing the log segment which just filled. */ #include @@ -30,37 +38,97 @@ #include #include +/** Maplog log file header segment. In a separate file */ + +typedef struct +{ + u8 maplog_major_version; /**< library major version number */ + u8 maplog_minor_version; /**< library minor version number */ + u8 maplog_patch_version; /**< library patch version number */ + u8 maplog_flag_wrapped; /**< log has wrapped */ + u32 application_id; /**< application identifier */ + u8 application_major_version; /**< application major version number */ + u8 application_minor_version; /**< application minor version number */ + u8 application_patch_version; /**< application patch version number */ + u8 maplog_flag_circular; /**< log is circular */ + u32 record_size_in_cachelines; /**< record size in cache lines */ + u32 cacheline_size; /**< cache line size */ + u64 file_size_in_records; /**< file size in records */ + u64 number_of_records; /**< number of records in entire log */ + u64 number_of_files; /**< number of files in entire log */ + u8 file_basename[256]; /**< file basename */ +} clib_maplog_header_t; + +#define MAPLOG_MAJOR_VERSION 1 +#define MAPLOG_MINOR_VERSION 1 +#define MAPLOG_PATCH_VERSION 0 + +/** Process-private main data structure */ + typedef struct { - /* rw: atomic ticket-counter, file index */ CLIB_CACHE_LINE_ALIGN_MARK (cacheline1); + /** rw cache line: atomic ticket-counter, file index */ volatile u64 next_record_index; - u64 file_size_in_records; /**< power of two */ - u32 log2_file_size_in_records; - volatile u32 current_file_index; - volatile u32 flags; + /** file size in records, rounded to a power of two */ + u64 file_size_in_records; + u32 log2_file_size_in_records; /**< lg file size in records */ + volatile u32 current_file_index; /**< current file index */ + volatile u32 flags; /**< flags, currently just "init" or not */ - /* ro: size parameters */ + /* read-mostly cache line: size parameters, file names, etc. */ CLIB_CACHE_LINE_ALIGN_MARK (cacheline2); - u32 record_size_in_cachelines; + u32 record_size_in_cachelines; /**< record size in cache lines */ /* double-buffered mmap'ed logfiles */ - volatile u8 *file_baseva[2]; - u8 *filenames[2]; + volatile u8 *file_baseva[2]; /**< active segment base addresses */ + u8 *filenames[2]; /**< active segment file names */ /* vector not c-string */ - u8 *file_basename; + u8 *file_basename; /**< basename, e.g. "/tmp/mylog" */ + u8 *header_filename; /**< log header file name */ } clib_maplog_main_t; -int clib_maplog_init (clib_maplog_main_t * mm, char *file_basename, - u64 file_size, u32 record_size_in_bytes); +/* flag bits */ +#define CLIB_MAPLOG_FLAG_INIT (1<<0) +#define CLIB_MAPLOG_FLAG_CIRCULAR (1<<1) +#define CLIB_MAPLOG_FLAG_WRAPPED (1<<2) +/** log initialization structure */ +typedef struct +{ + clib_maplog_main_t *mm; /**< pointer to the main structure */ + char *file_basename; /**< file base name */ + u64 file_size_in_bytes; /**< file size in bytes */ + u32 record_size_in_bytes; /**< record size in bytes */ + u32 application_id; /**< application identifier */ + u8 application_major_version; /**< application major version number */ + u8 application_minor_version; /**< application minor version number */ + u8 application_patch_version; /**< application patch version number */ + u8 maplog_is_circular; /**< single, circular log */ +} clib_maplog_init_args_t; + +/* function prototypes */ + +int clib_maplog_init (clib_maplog_init_args_t * ap); +void clib_maplog_update_header (clib_maplog_main_t * mm); void clib_maplog_close (clib_maplog_main_t * mm); +int clib_maplog_process (char *file_basename, void *fp_arg); -#define CLIB_MAPLOG_FLAG_INIT (1<<0) +format_function_t format_maplog_header; u8 *_clib_maplog_get_entry_slowpath (clib_maplog_main_t * mm, u64 my_record_index); +/** + * @brief Obtain a log entry pointer + * + * Increments the atomic ticket counter, and returns a pointer to + * the newly-allocated log entry. The slowpath function replaces + * a full log segment with a new/fresh/empty log segment + * + * @param[in] mm maplog object pointer + * @return pointer to the allocated log entry + */ static inline void * clib_maplog_get_entry (clib_maplog_main_t * mm) { @@ -69,14 +137,20 @@ clib_maplog_get_entry (clib_maplog_main_t * mm) ASSERT (mm->flags & CLIB_MAPLOG_FLAG_INIT); - my_record_index = __sync_fetch_and_add (&mm->next_record_index, 1); + my_record_index = clib_atomic_fetch_add (&mm->next_record_index, 1); /* Time to unmap and create a new logfile? */ if (PREDICT_FALSE ((my_record_index & (mm->file_size_in_records - 1)) == 0)) { - /* Yes, but not the very first time... (;-)... */ - if (my_record_index) - return _clib_maplog_get_entry_slowpath (mm, my_record_index); + /* Regular log? Switch file... */ + if (!(mm->flags & CLIB_MAPLOG_FLAG_CIRCULAR)) + { + /* Yes, but not the very first time... (;-)... */ + if (my_record_index) + return _clib_maplog_get_entry_slowpath (mm, my_record_index); + } + else /* Circular log: set the wrap bit and move along */ + mm->flags |= CLIB_MAPLOG_FLAG_WRAPPED; /* FALLTHROUGH */ }