From be1c63411addba3ad750eb4fdfc50b97bc82825e Mon Sep 17 00:00:00 2001 From: Olaf Kirch Date: Fri, 1 Dec 2006 10:39:12 +0100 Subject: [PATCH] blktrace: add timestamp message This adds a new timestamp message to blktrace, giving the timeofday when we starting tracing. This helps user space correlate block trace events with eg an application strace. This requires a (compatible) update to blkparse. The changed blkparse is still able to process traces generated by older kernels, and older versions of blkparse should silently ignore the new records (because they have a pid of 0). Signed-off-by: Olaf Kirch Signed-off-by: Jens Axboe --- block/blktrace.c | 57 ++++++++++++++++++++++++++++++++++---------- include/linux/blktrace_api.h | 12 ++++++++++ 2 files changed, 57 insertions(+), 12 deletions(-) diff --git a/block/blktrace.c b/block/blktrace.c index 135593c..562ca7c 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -22,30 +22,61 @@ #include #include #include +#include #include static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, }; static unsigned int blktrace_seq __read_mostly = 1; /* + * Send out a notify message. + */ +static inline unsigned int trace_note(struct blk_trace *bt, + pid_t pid, int action, + const void *data, size_t len) +{ + struct blk_io_trace *t; + int cpu = smp_processor_id(); + + t = relay_reserve(bt->rchan, sizeof(*t) + len); + if (t == NULL) + return 0; + + t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; + t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu); + t->device = bt->dev; + t->action = action; + t->pid = pid; + t->cpu = cpu; + t->pdu_len = len; + memcpy((void *) t + sizeof(*t), data, len); + return blktrace_seq; +} + +/* * Send out a notify for this process, if we haven't done so since a trace * started */ static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) { - struct blk_io_trace *t; + tsk->btrace_seq = trace_note(bt, tsk->pid, + BLK_TN_PROCESS, + tsk->comm, sizeof(tsk->comm)); +} - t = relay_reserve(bt->rchan, sizeof(*t) + sizeof(tsk->comm)); - if (t) { - t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; - t->device = bt->dev; - t->action = BLK_TC_ACT(BLK_TC_NOTIFY); - t->pid = tsk->pid; - t->cpu = smp_processor_id(); - t->pdu_len = sizeof(tsk->comm); - memcpy((void *) t + sizeof(*t), tsk->comm, t->pdu_len); - tsk->btrace_seq = blktrace_seq; - } +static void trace_note_time(struct blk_trace *bt) +{ + struct timespec now; + unsigned long flags; + u32 words[2]; + + getnstimeofday(&now); + words[0] = now.tv_sec; + words[1] = now.tv_nsec; + + local_irq_save(flags); + trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); + local_irq_restore(flags); } static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, @@ -394,6 +425,8 @@ static int blk_trace_startstop(request_queue_t *q, int start) blktrace_seq++; smp_mb(); bt->trace_state = Blktrace_running; + + trace_note_time(bt); ret = 0; } } else { diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index b99a714..3680ff9a 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -50,6 +50,15 @@ enum blktrace_act { }; /* + * Notify events. + */ +enum blktrace_notify { + __BLK_TN_PROCESS = 0, /* establish pid/name mapping */ + __BLK_TN_TIMESTAMP, /* include system clock */ +}; + + +/* * Trace actions in full. Additionally, read or write is masked */ #define BLK_TA_QUEUE (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE)) @@ -68,6 +77,9 @@ enum blktrace_act { #define BLK_TA_BOUNCE (__BLK_TA_BOUNCE) #define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE)) +#define BLK_TN_PROCESS (__BLK_TN_PROCESS | BLK_TC_ACT(BLK_TC_NOTIFY)) +#define BLK_TN_TIMESTAMP (__BLK_TN_TIMESTAMP | BLK_TC_ACT(BLK_TC_NOTIFY)) + #define BLK_IO_TRACE_MAGIC 0x65617400 #define BLK_IO_TRACE_VERSION 0x07 -- cgit v1.1