Re: [PATCH v2 11/12] scsi: ufs: add trace event for ufs commands
From: Subhash Jadavani
Date: Tue Dec 13 2016 - 16:00:08 EST
On 2016-12-13 12:22, Steven Rostedt wrote:
On Tue, 13 Dec 2016 11:52:16 -0800
Subhash Jadavani <subhashj@xxxxxxxxxxxxxx> wrote:
From: Lee Susman <lsusman@xxxxxxxxxxxxxx>
Use the ftrace infrastructure to conditionally trace ufs command
events.
New trace event is created, which samples the following ufs command
data:
- device name
- optional identification string
- task tag
- doorbell register
- number of transfer bytes
- interrupt status register
- request start LBA
- command opcode
Currently we only fully trace read(10) and write(10) commands.
All other commands which pass through ufshcd_send_command() will be
printed with "-1" in the lba and transfer_len fields.
Usage:
echo 1 > /sys/kernel/debug/tracing/events/ufs/enable
cat /sys/kernel/debug/tracing/trace_pipe
Signed-off-by: Lee Susman <lsusman@xxxxxxxxxxxxxx>
Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 52
+++++++++++++++++++++++++++++++++++++++++++++-
include/trace/events/ufs.h | 38 +++++++++++++++++++++++++++++++++
2 files changed, 89 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 33f3947..926d1ef 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -301,6 +301,51 @@ static inline void
ufshcd_remove_non_printable(char *val)
*val = ' ';
}
+#ifdef CONFIG_TRACEPOINTS
+static void ufshcd_add_command_trace(struct ufs_hba *hba,
+ unsigned int tag, const char *str)
Is this function only to use if you enable the tracepoint? Is there
anything here doing something that wouldn't be enabled if tracing
wasn't configured in?
Also, if this is in a code execution path, it appears that you do this
work regardless if the tracer is running or not.
That's true, need to fix this.
+{
+ sector_t lba = -1;
+ u8 opcode = 0;
+ u32 intr, doorbell;
+ struct ufshcd_lrb *lrbp;
+ int transfer_len = -1;
+
+ lrbp = &hba->lrb[tag];
+
+ if (lrbp->cmd) { /* data phase exists */
+ opcode = (u8)(*lrbp->cmd->cmnd);
+ if ((opcode == READ_10) || (opcode == WRITE_10)) {
+ /*
+ * Currently we only fully trace read(10) and write(10)
+ * commands
+ */
+ if (lrbp->cmd->request && lrbp->cmd->request->bio)
+ lba =
+ lrbp->cmd->request->bio->bi_iter.bi_sector;
+ transfer_len = be32_to_cpu(
+ lrbp->ucd_req_ptr->sc.exp_data_transfer_len);
+ }
+ }
+
+ intr = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
+ doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+ trace_ufshcd_command(dev_name(hba->dev), str, tag,
+ doorbell, transfer_len, intr, lba, opcode);
+}
+
+static inline void ufshcd_cond_add_cmd_trace(struct ufs_hba *hba,
+ unsigned int tag, const char *str)
+{
+ ufshcd_add_command_trace(hba, tag, str);
+}
+#else
+static inline void ufshcd_cond_add_cmd_trace(struct ufs_hba *hba,
+ unsigned int tag, const char *str)
+{
+}
+#endif
If my above assumptions are correct, I recommend removing the above
#if, and have it always configured. Then...
Agreed.
+
static void ufshcd_print_host_regs(struct ufs_hba *hba)
{
/*
@@ -1193,6 +1238,7 @@ void ufshcd_send_command(struct ufs_hba *hba,
unsigned int task_tag)
ufshcd_writel(hba, 1 << task_tag, REG_UTP_TRANSFER_REQ_DOOR_BELL);
/* Make sure that doorbell is committed immediately */
wmb();
Add:
if (trace_ufshcd_command_enabled())
ufshcd_cond_add_cmd_trace(hba, task_tag, "send");
For one thing, the function only gets called if the tracepoint
ufshcd_command is enabled.
Now if CONFIG_TRACEPOINTS is not configured in, then the
trace_ufshcd_command_enabled() turns into a "return false;" which one
would hope that gcc will take that as a if (0) and optimized the entire
function out of existence.
This would make the code a bit cleaner and accomplish the same.
Agreed, will try this. Thank you.
-- Steve
}
/**
@@ -3982,6 +4028,7 @@ static void __ufshcd_transfer_req_compl(struct
ufs_hba *hba,
lrbp = &hba->lrb[index];
cmd = lrbp->cmd;
if (cmd) {
+ ufshcd_cond_add_cmd_trace(hba, index, "complete");
result = ufshcd_transfer_rsp_status(hba, lrbp);
scsi_dma_unmap(cmd);
cmd->result = result;
@@ -3993,8 +4040,11 @@ static void __ufshcd_transfer_req_compl(struct
ufs_hba *hba,
__ufshcd_release(hba);
} else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE ||
lrbp->command_type == UTP_CMD_TYPE_UFS_STORAGE) {
- if (hba->dev_cmd.complete)
+ if (hba->dev_cmd.complete) {
+ ufshcd_cond_add_cmd_trace(hba, index,
+ "dev_complete");
complete(hba->dev_cmd.complete);
+ }
}
}
diff --git a/include/trace/events/ufs.h b/include/trace/events/ufs.h
index 8bce504..d0ed0cf 100644
--- a/include/trace/events/ufs.h
+++ b/include/trace/events/ufs.h
@@ -183,6 +183,44 @@
TP_PROTO(const char *dev_name, int err, s64 usecs,
const char *dev_state, const char *link_state),
TP_ARGS(dev_name, err, usecs, dev_state, link_state));
+
+TRACE_EVENT(ufshcd_command,
+ TP_PROTO(const char *dev_name, const char *str, unsigned int tag,
+ u32 doorbell, int transfer_len, u32 intr, u64 lba,
+ u8 opcode),
+
+ TP_ARGS(dev_name, str, tag, doorbell, transfer_len, intr, lba,
opcode),
+
+ TP_STRUCT__entry(
+ __string(dev_name, dev_name)
+ __string(str, str)
+ __field(unsigned int, tag)
+ __field(u32, doorbell)
+ __field(int, transfer_len)
+ __field(u32, intr)
+ __field(u64, lba)
+ __field(u8, opcode)
+ ),
+
+ TP_fast_assign(
+ __assign_str(dev_name, dev_name);
+ __assign_str(str, str);
+ __entry->tag = tag;
+ __entry->doorbell = doorbell;
+ __entry->transfer_len = transfer_len;
+ __entry->intr = intr;
+ __entry->lba = lba;
+ __entry->opcode = opcode;
+ ),
+
+ TP_printk(
+ "%s: %s: tag: %u, DB: 0x%x, size: %d, IS: %u, LBA: %llu, opcode:
0x%x",
+ __get_str(str), __get_str(dev_name), __entry->tag,
+ __entry->doorbell, __entry->transfer_len,
+ __entry->intr, __entry->lba, (u32)__entry->opcode
+ )
+);
+
#endif /* if !defined(_TRACE_UFS_H) ||
defined(TRACE_HEADER_MULTI_READ) */
/* This part must be outside protection */
--
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