diff options
Diffstat (limited to 'benchmarks/bonnie/DESCR')
| -rw-r--r-- | benchmarks/bonnie/DESCR | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/benchmarks/bonnie/DESCR b/benchmarks/bonnie/DESCR index a08bfc07576..af3efdf9a7b 100644 --- a/benchmarks/bonnie/DESCR +++ b/benchmarks/bonnie/DESCR @@ -1,17 +1,25 @@ -Bonnie: Filesystem Benchmark Program +Bonnie: A simple Filesystem Benchmark Program -Bonnie tests the speed of file I/O using standard C library calls. -It does reads and writes of blocks, testing for the limit of sustained -data rate (usually limited by the drive or controller) and updates on -a file (better simulating normal operating conditions and quite dependent -on drive and OS optimisations). -The per character read and write tests are generally limited by CPU speed -only on current generation hardware. It takes some 35 SPECint92 to read -or write a file at a rate of 1MB/s using getc() and putc(). -The seek tests are dependent on the buffer cache size, since the fraction -of disk blocks that fits into the buffer cache will be found without any -disk operation and will contribute zero seek time readings. I.e. if the -buffer cache is 16MB and the Bonnie test file is 32MB in size, then the -seek time will come out as half its real value. The seek time includes -rotational delay, and will thus always come out higher than specified for -a drive. +Bonnie tests the speed of sequential file I/O using standard C library +calls. It does reads and writes of characters using STDIO; and of +blocks using system calls. Then it does a sequential pass of reading +every block, modifying one byte, and writing it back; and finally it +does random seeks followed by reads and writes of blocks. It reports +the average sustained data rate (usually limited by the drive or +controller). It is quite dependent on hardware and OS optimisations. + +The per character read and write tests are generally limited by CPU +speed except on the fastest of systems. It takes some 35 SPECint92 to +read or write a file at a rate of 1MB/s using getc() and putc(). + +The input tests, particularly the block reads, are highly dependent on +the buffer cache size. A file size of at least four times available RAM +is needed to effectivley mask the effects of the buffer cache. + +The seek tests are also dependent on the buffer cache size, since the +fraction of disk blocks which fit into the buffer cache will be found +without any actual disk access and will contribute little or no apparent +seek time to the mesurements. I.e. if the buffer cache is 16MB and the +Bonnie test file is 32MB in size, then the seek time will come out as +about half its real value. The seek time includes rotational delay, and +will thus always come out higher than the specified value for a drive. |