[PATCH v2 09/10] nvme/mdev - Add inline performance measurments

Maxim Levitsky
2019-05-02T11:49:45Z

This code might not be needed to be merged in the final version

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
drivers/nvme/mdev/instance.c | 62 ++++++++++++++++++++++++++++++++++++
drivers/nvme/mdev/io.c | 21 ++++++++++++
drivers/nvme/mdev/irq.c | 6 ++++
drivers/nvme/mdev/priv.h | 13 ++++++++
drivers/nvme/mdev/vctrl.c | 3 ++
5 files changed, 105 insertions(+)

diff --git a/drivers/nvme/mdev/instance.c b/drivers/nvme/mdev/instance.c
index 0e5ba5a9269f..d692b2bf2ef2 100644
--- a/drivers/nvme/mdev/instance.c
+++ b/drivers/nvme/mdev/instance.c
@@ -771,6 +771,62 @@ static struct attribute *nvme_mdev_dev_settings_atttributes[] = {
NULL
};

+/* show perf stats */
+static ssize_t stats_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nvme_mdev_vctrl *vctrl = dev_to_vctrl(dev);
+ struct nvme_mdev_perf *perf;
+
+ if (!vctrl)
+ return -ENODEV;
+
+ perf = &vctrl->perf;
+
+ return sprintf(buf,
+ "%u %llu %llu %llu %llu %llu %llu\n",
+
+ tsc_khz,
+
+ perf->cmds_started,
+ perf->cycles_send_to_hw,
+
+ perf->cmds_complete,
+ perf->cycles_receive_from_hw,
+
+ perf->interrupts_sent,
+ perf->cycles_irq_delivery);
+}
+
+/* clear the perf stats */
+static ssize_t stats_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ bool val;
+ int ret;
+ struct nvme_mdev_vctrl *vctrl = dev_to_vctrl(dev);
+
+ if (!vctrl)
+ return -ENODEV;
+ ret = kstrtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ if (!val)
+ return -EINVAL;
+
+ memset(&vctrl->perf, 0, sizeof(vctrl->perf));
+ return count;
+}
+
+static DEVICE_ATTR_RW(stats);
+
+static struct attribute *nvme_mdev_dev_debug_attributes[] = {
+ &dev_attr_stats.attr,
+ NULL
+};
+
static const struct attribute_group nvme_mdev_ns_attr_group = {
.name = "namespaces",
.attrs = nvme_mdev_dev_ns_atttributes,
@@ -781,9 +837,15 @@ static const struct attribute_group nvme_mdev_setting_attr_group = {
.attrs = nvme_mdev_dev_settings_atttributes,
};

+static const struct attribute_group nvme_mdev_debug_attr_group = {
+ .name = "debug",
+ .attrs = nvme_mdev_dev_debug_attributes,
+};
+
static const struct attribute_group *nvme_mdev_dev_attributte_groups[] = {
&nvme_mdev_ns_attr_group,
&nvme_mdev_setting_attr_group,
+ &nvme_mdev_debug_attr_group,
NULL,
};

diff --git a/drivers/nvme/mdev/io.c b/drivers/nvme/mdev/io.c
index 59837540fec2..39550d0e3649 100644
--- a/drivers/nvme/mdev/io.c
+++ b/drivers/nvme/mdev/io.c
@@ -9,6 +9,7 @@
#include <linux/nvme.h>
#include <linux/timekeeping.h>
#include <linux/ktime.h>
+#include <asm/msr.h>
#include "priv.h"

@@ -251,6 +252,9 @@ static bool nvme_mdev_io_process_sq(struct io_ctx *ctx, u16 sqid)
struct nvme_vsq *vsq = &ctx->vctrl->vsqs[sqid];
u16 ucid;
int ret;
+ unsigned long long c1, c2;
+
+ c1 = rdtsc();

/* If host queue is full, we can't process a command
* as a command will likely result in passthrough
@@ -289,6 +293,12 @@ static bool nvme_mdev_io_process_sq(struct io_ctx *ctx, u16 sqid)

nvme_mdev_vsq_cmd_done_io(ctx->vctrl, sqid, ucid, ret);
}
+
+ c2 = rdtsc();
+
+ ctx->vctrl->perf.cmds_started++;
+ ctx->vctrl->perf.cycles_send_to_hw += (c2 - c1);
+
return true;
}

@@ -304,6 +314,10 @@ static int nvme_mdev_io_process_hwq(struct io_ctx *ctx, u16 hwq)
int n, i;
struct nvme_ext_cmd_result res[16];

+ unsigned long long c1, c2;
+
+ c1 = rdtsc();
+
/* process the completions from the hardware */
n = nvme_mdev_hctrl_hq_poll(ctx->hctrl, hwq, res, 16);
if (n == -1)
@@ -321,6 +335,13 @@ static int nvme_mdev_io_process_hwq(struct io_ctx *ctx, u16 hwq)

nvme_mdev_vsq_cmd_done_io(ctx->vctrl, qid, cid, status);
}
+
+ if (n > 0) {
+ c2 = rdtsc();
+ ctx->vctrl->perf.cmds_complete += n;
+ ctx->vctrl->perf.cycles_receive_from_hw += (c2 - c1);
+ }
+
return n;
}

diff --git a/drivers/nvme/mdev/irq.c b/drivers/nvme/mdev/irq.c
index 5809cdb4d84c..b6010a69b584 100644
--- a/drivers/nvme/mdev/irq.c
+++ b/drivers/nvme/mdev/irq.c
@@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include "priv.h"
+#include <asm/msr.h>

/* Setup the interrupt subsystem */
void nvme_mdev_irqs_setup(struct nvme_mdev_vctrl *vctrl)
@@ -253,12 +254,17 @@ void nvme_mdev_irq_cond_trigger(struct nvme_mdev_vctrl *vctrl,
unsigned int index)
{
struct nvme_mdev_user_irq *irq = &vctrl->irqs.vecs[index];
+ unsigned long long c1, c2;

if (irq->irq_pending_cnt == 0)
return;

if (!nvme_mdev_irq_coalesce(vctrl, irq)) {
+ vctrl->perf.interrupts_sent++;
+ c1 = rdtsc();
nvme_mdev_irq_trigger(vctrl, index);
+ c2 = rdtsc();
nvme_mdev_irq_clear(vctrl, index);
+ vctrl->perf.cycles_irq_delivery += (c2 - c1);
}
}
diff --git a/drivers/nvme/mdev/priv.h b/drivers/nvme/mdev/priv.h
index 9f65e46c1ab2..a11a1842957d 100644
--- a/drivers/nvme/mdev/priv.h
+++ b/drivers/nvme/mdev/priv.h
@@ -245,6 +245,17 @@ struct nvme_mdev_io_region {
unsigned int mmap_area_size;
};

+struct nvme_mdev_perf {
+ /* number of IO commands received */
+ unsigned long long cmds_started;
+ unsigned long long cmds_complete;
+ unsigned long long interrupts_sent;
+
+ unsigned long long cycles_send_to_hw;
+ unsigned long long cycles_receive_from_hw;
+ unsigned long long cycles_irq_delivery;
+};
+
/*Virtual NVME controller state */
struct nvme_mdev_vctrl {
struct kref ref;
@@ -301,6 +312,8 @@ struct nvme_mdev_vctrl {
char serial[9];

bool vctrl_paused; /* true when the host device paused our IO */
+
+ struct nvme_mdev_perf perf;
};

/* mdev instance type*/
diff --git a/drivers/nvme/mdev/vctrl.c b/drivers/nvme/mdev/vctrl.c
index 87bc7c435c0c..d23b543dfd52 100644
--- a/drivers/nvme/mdev/vctrl.c
+++ b/drivers/nvme/mdev/vctrl.c
@@ -242,6 +242,9 @@ int nvme_mdev_vctrl_open(struct nvme_mdev_vctrl *vctrl)

nvme_mdev_mmio_open(vctrl);
vctrl->inuse = true;
+
+ memset(&vctrl->perf, 0, sizeof(vctrl->perf));
+
out:
mutex_unlock(&vctrl->lock);
return ret;
--
2.17.2