Re: [PATCH 7/9] readahead: add vfs/readahead tracing event
From: Jan Kara <jack@suse.cz>
Date: 2011-11-29 15:22:28
Also in:
linux-fsdevel, lkml
On Tue 29-11-11 21:09:07, Wu Fengguang wrote:
This is very useful for verifying whether the readahead algorithms are working to the expectation. Example output: # echo 1 > /debug/tracing/events/vfs/readahead/enable # cp test-file /dev/null # cat /debug/tracing/trace # trimmed output readahead-initial(dev=0:15, ino=100177, req=0+2, ra=0+4-2, async=0) = 4 readahead-subsequent(dev=0:15, ino=100177, req=2+2, ra=4+8-8, async=1) = 8 readahead-subsequent(dev=0:15, ino=100177, req=4+2, ra=12+16-16, async=1) = 16 readahead-subsequent(dev=0:15, ino=100177, req=12+2, ra=28+32-32, async=1) = 32 readahead-subsequent(dev=0:15, ino=100177, req=28+2, ra=60+60-60, async=1) = 24 readahead-subsequent(dev=0:15, ino=100177, req=60+2, ra=120+60-60, async=1) = 0 CC: Ingo Molnar <redacted> CC: Jens Axboe <axboe@kernel.dk> CC: Steven Rostedt <rostedt@goodmis.org> CC: Peter Zijlstra <redacted> Acked-by: Rik van Riel <redacted> Signed-off-by: Wu Fengguang <redacted>
Looks OK. Acked-by: Jan Kara [off-list ref] Honza
quoted hunk ↗ jump to hunk
--- include/trace/events/vfs.h | 64 +++++++++++++++++++++++++++++++++++ mm/readahead.c | 5 ++ 2 files changed, 69 insertions(+)--- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-next/include/trace/events/vfs.h 2011-11-29 20:58:59.000000000 +0800@@ -0,0 +1,64 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM vfs + +#if !defined(_TRACE_VFS_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_VFS_H + +#include <linux/tracepoint.h> + +TRACE_EVENT(readahead, + TP_PROTO(struct address_space *mapping, + pgoff_t offset, + unsigned long req_size, + enum readahead_pattern pattern, + pgoff_t start, + unsigned long size, + unsigned long async_size, + unsigned int actual), + + TP_ARGS(mapping, offset, req_size, pattern, start, size, async_size, + actual), + + TP_STRUCT__entry( + __field( dev_t, dev ) + __field( ino_t, ino ) + __field( pgoff_t, offset ) + __field( unsigned long, req_size ) + __field( unsigned int, pattern ) + __field( pgoff_t, start ) + __field( unsigned int, size ) + __field( unsigned int, async_size ) + __field( unsigned int, actual ) + ), + + TP_fast_assign( + __entry->dev = mapping->host->i_sb->s_dev; + __entry->ino = mapping->host->i_ino; + __entry->offset = offset; + __entry->req_size = req_size; + __entry->pattern = pattern; + __entry->start = start; + __entry->size = size; + __entry->async_size = async_size; + __entry->actual = actual; + ), + + TP_printk("readahead-%s(dev=%d:%d, ino=%lu, " + "req=%lu+%lu, ra=%lu+%d-%d, async=%d) = %d", + ra_pattern_names[__entry->pattern], + MAJOR(__entry->dev), + MINOR(__entry->dev), + __entry->ino, + __entry->offset, + __entry->req_size, + __entry->start, + __entry->size, + __entry->async_size, + __entry->start > __entry->offset, + __entry->actual) +); + +#endif /* _TRACE_VFS_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> --- linux-next.orig/mm/readahead.c 2011-11-29 20:58:53.000000000 +0800 +++ linux-next/mm/readahead.c 2011-11-29 20:59:20.000000000 +0800@@ -29,6 +29,9 @@ static const char * const ra_pattern_nam [RA_PATTERN_ALL] = "all", }; +#define CREATE_TRACE_POINTS +#include <trace/events/vfs.h> + /* * Initialise a struct file's readahead state. Assumes that the caller has * memset *ra to zero.@@ -215,6 +218,8 @@ static inline void readahead_event(struc for_mmap, for_metadata, pattern, start, size, async_size, actual); #endif + trace_readahead(mapping, offset, req_size, + pattern, start, size, async_size, actual); } --To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Jan Kara [off-list ref] SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>