mirror of
https://github.com/SCST-project/scst.git
synced 2026-05-19 03:31:26 +00:00
Merge branch 'svn-trunk'
This commit is contained in:
Bart Van Assche
@@ -160,7 +160,7 @@ Value(s): value
|
||||
Value(s): user->name
|
||||
.RE
|
||||
|
||||
"succesfull login by %s"
|
||||
"successful login by %s"
|
||||
.RS
|
||||
Value(s): user->name
|
||||
.RE
|
||||
|
||||
@@ -185,6 +185,11 @@ default.
|
||||
N_Port ID Virtualization
|
||||
------------------------
|
||||
|
||||
Unfortunately, due to severe problems in the original qla2xxx driver,
|
||||
NPIV in this version is not supported. If you need NPIV, you can use
|
||||
previous version 2.1 of this driver.
|
||||
|
||||
|
||||
N_Port ID Virtualization (NPIV) is a Fibre Channel facility allowing
|
||||
multiple N_Port IDs to share a single physical N_Port. NPIV is fully
|
||||
supported by this driver. You must have 24xx+ ISPs with NPIV-supporting
|
||||
|
||||
58
scst/README
58
scst/README
@@ -450,6 +450,14 @@ following entries:
|
||||
have different IDs and SNs. For instance, VDISK dev handler uses this
|
||||
ID to generate T10 vendor specific identifier and SN of the devices.
|
||||
|
||||
- poll_us - if polling is desired, sets how many us each SCST thread
|
||||
is polling its queue after it became empty in a hope that a new
|
||||
command can come. In some cases, polling can significantly increase
|
||||
IOPS, especially if low power states on CPU not disabled, because on
|
||||
high IOPS polling could be cheaper comparing to spending significant
|
||||
time on entering, then exiting CPU low power states + corresponding
|
||||
context switches. Disabled, i.e. set to 0, by default.
|
||||
|
||||
- suspend - globally suspends or releases all SCSI activities on all
|
||||
devices. Useful for mass management, like adding or deleting LUNs.
|
||||
Writing to it value v:
|
||||
@@ -2186,13 +2194,6 @@ you, so the resulting performance will, in average, be better
|
||||
(sometimes, much better) than with other SCSI targets. But in some cases
|
||||
you can by manual tuning improve it even more.
|
||||
|
||||
If you want to get maximum performance from your target, RHEL/CentOS 5.x
|
||||
kernels are not recommended on both target and initiators, if you are
|
||||
using Linux initiators, because those kernels are based on very outdated
|
||||
2.6.18 kernel, hence, missed >3 years of important improvements in the
|
||||
kernel's storage area. You should use at least long maintained vanilla
|
||||
2.6.27.x kernel, although 2.6.29+ would be even better.
|
||||
|
||||
Before doing any performance measurements note that performance results
|
||||
are very much dependent from your type of load, so it is crucial that
|
||||
you choose access mode (FILEIO, BLOCKIO, O_DIRECT, pass-through), which
|
||||
@@ -2215,11 +2216,18 @@ In order to get the maximum performance you should:
|
||||
|
||||
- Disable in Makefile CONFIG_SCST_TRACING and CONFIG_SCST_DEBUG.
|
||||
|
||||
Note, by disabling CONFIG_SCST_TRACING and CONFIG_SCST_DEBUG you are
|
||||
disabling many useful SCST diagnostic messages, which can significantly
|
||||
help in many troubleshooting cases. So, if you may consider to keep
|
||||
CONFIG_SCST_TRACING, its performance impact is very limited.
|
||||
|
||||
IMPORTANT: The development version of SCST in the SVN is optimized for
|
||||
========= development and bug hunting, not for performance. To reconfigure
|
||||
it for performance you should run "make 2perf" in the
|
||||
root of your source code (e.g. trunk/). It will set the above
|
||||
options as needed. The only option it doesn't set is
|
||||
|
||||
it for performance you should run "make 2perf" or "make
|
||||
2release" (to keep CONFIG_SCST_TRACING) in the root of your
|
||||
source code (e.g. trunk/). It will set the above options as
|
||||
needed. The only option it doesn't set is
|
||||
CONFIG_SCST_TEST_IO_IN_SIRQ, so, if needed, you should change
|
||||
it manually.
|
||||
|
||||
@@ -2416,6 +2424,17 @@ context might be done on the same CPUs as SSD devices' threads doing data
|
||||
transfers. As the result, those threads won't receive all the processing
|
||||
power of those CPUs and perform worse.
|
||||
|
||||
10. If your storage is capable of operation on hundreds of thousands
|
||||
IOPS level, you can use poll_us sysfs attribute to set how many us each
|
||||
SCST thread is polling its queue after it became empty in a hope that a
|
||||
new command can come. In some cases, polling can significantly increase
|
||||
IOPS, especially if low power states on CPU not disabled, because on
|
||||
high IOPS polling could be cheaper comparing to spending significant
|
||||
time on entering, then exiting CPU low power states + corresponding
|
||||
context switches. Polling is disabled by default. The recommended value
|
||||
to start from is 5-10 us. Then you can increase or decrease it to see if
|
||||
your IOPS are increasing or decreasing.
|
||||
|
||||
|
||||
Commands suspending takes too long
|
||||
----------------------------------
|
||||
@@ -2470,7 +2489,7 @@ issues:
|
||||
1. Ignore incoming task management (TM) commands. It's fine if there are
|
||||
not too many of them, so average performance isn't hurt and the
|
||||
corresponding device isn't getting put offline, i.e. if the backstorage
|
||||
isn't too slow.
|
||||
isn't a way too slow.
|
||||
|
||||
2. Decrease /sys/block/sdX/device/queue_depth on the initiator in case
|
||||
if it's Linux (see below how) or/and SCST_MAX_TGT_DEV_COMMANDS constant
|
||||
@@ -2502,11 +2521,9 @@ By default, this timeout is 30 or 60 seconds, depending on your distribution.
|
||||
|
||||
5. Increase speed of the target's backstorage.
|
||||
|
||||
6. Implement in SCST dynamic I/O flow control, so queue depth on the
|
||||
target is dynamically decreased/increased based on how slow/fast the
|
||||
backstorage speed comparing to the target link. See "Dynamic I/O flow
|
||||
control" section on http://scst.sourceforge.net/contributing.html page
|
||||
for possible implementation idea.
|
||||
6. Implement in SCST QoS, so queue depth size on the target is
|
||||
dynamically adjusted, hence worst case initiator seen latencies are
|
||||
controlled.
|
||||
|
||||
Next, consider the case of too slow link between initiator and target,
|
||||
when the initiator tries to simultaneously push N commands to the target
|
||||
@@ -2516,13 +2533,8 @@ command, hence one or more commands in the tail of the queue can not be
|
||||
served on time less than the timeout, so the initiator will decide that
|
||||
they are stuck on the target and will try to recover.
|
||||
|
||||
To workaround/fix this issue in this case you can use ways 1, 2, 3, 6
|
||||
above or (7): increase speed of the link between target and initiator.
|
||||
But for some initiators implementations for WRITE commands there might
|
||||
be cases when target has no way to detect the issue, so dynamic I/O flow
|
||||
control will not be able to help. In those cases you could also need on
|
||||
the initiator(s) to either decrease the queue depth (way 2), or increase
|
||||
the corresponding timeout (way 3).
|
||||
To workaround/fix this issue in this case you can use ways 1, 2, 3 above
|
||||
or (7): increase speed of the link between target and initiator.
|
||||
|
||||
Note, that logged messages about QUEUE_FULL status are quite different
|
||||
by nature. This is a normal work, just SCSI flow control in action.
|
||||
|
||||
@@ -314,6 +314,14 @@ following entries:
|
||||
have different IDs and SNs. For instance, VDISK dev handler uses this
|
||||
ID to generate T10 vendor specific identifier and SN of the devices.
|
||||
|
||||
- poll_us - if polling is desired, sets how many us each SCST thread
|
||||
is polling its queue after it became empty in a hope that a new
|
||||
command can come. In some cases, polling can significantly increase
|
||||
IOPS, especially if low power states on CPU not disabled, because on
|
||||
high IOPS polling could be cheaper comparing to spending significant
|
||||
time on entering, then exiting CPU low power states + corresponding
|
||||
context switches. Disabled, i.e. set to 0, by default.
|
||||
|
||||
- suspend - globally suspends or releases all SCSI activities on all
|
||||
devices. Useful for mass management, like adding or deleting LUNs.
|
||||
Writing to it value v:
|
||||
@@ -2042,6 +2050,11 @@ In order to get the maximum performance you should:
|
||||
|
||||
- Disable in Makefile CONFIG_SCST_TRACING and CONFIG_SCST_DEBUG.
|
||||
|
||||
Note, by disabling CONFIG_SCST_TRACING and CONFIG_SCST_DEBUG you are
|
||||
disabling many useful SCST diagnostic messages, which can significantly
|
||||
help in many troubleshooting cases. So, if you may consider to keep
|
||||
CONFIG_SCST_TRACING, its performance impact is very limited.
|
||||
|
||||
4. Make sure you have io_grouping_type option set correctly, especially
|
||||
in the following cases:
|
||||
|
||||
@@ -2230,6 +2243,17 @@ context might be done on the same CPUs as SSD devices' threads doing data
|
||||
transfers. As the result, those threads won't receive all the processing
|
||||
power of those CPUs and perform worse.
|
||||
|
||||
10. If your storage is capable of operation on hundreds of thousands
|
||||
IOPS level, you can use poll_us sysfs attribute to set how many us each
|
||||
SCST thread is polling its queue after it became empty in a hope that a
|
||||
new command can come. In some cases, polling can significantly increase
|
||||
IOPS, especially if low power states on CPU not disabled, because on
|
||||
high IOPS polling could be cheaper comparing to spending significant
|
||||
time on entering, then exiting CPU low power states + corresponding
|
||||
context switches. Polling is disabled by default. The recommended value
|
||||
to start from is 5-10 us. Then you can increase or decrease it to see if
|
||||
your IOPS are increasing or decreasing.
|
||||
|
||||
|
||||
Commands suspending takes too long
|
||||
----------------------------------
|
||||
@@ -2284,7 +2308,7 @@ issues:
|
||||
1. Ignore incoming task management (TM) commands. It's fine if there are
|
||||
not too many of them, so average performance isn't hurt and the
|
||||
corresponding device isn't getting put offline, i.e. if the backstorage
|
||||
isn't too slow.
|
||||
isn't a way too slow.
|
||||
|
||||
2. Decrease /sys/block/sdX/device/queue_depth on the initiator in case
|
||||
if it's Linux (see below how) or/and SCST_MAX_TGT_DEV_COMMANDS constant
|
||||
@@ -2316,11 +2340,9 @@ By default, this timeout is 30 or 60 seconds, depending on your distribution.
|
||||
|
||||
5. Increase speed of the target's backstorage.
|
||||
|
||||
6. Implement in SCST dynamic I/O flow control, so queue depth on the
|
||||
target is dynamically decreased/increased based on how slow/fast the
|
||||
backstorage speed comparing to the target link. See "Dynamic I/O flow
|
||||
control" section on http://scst.sourceforge.net/contributing.html page
|
||||
for possible implementation idea.
|
||||
6. Implement in SCST QoS, so queue depth size on the target is
|
||||
dynamically adjusted, hence worst case initiator seen latencies are
|
||||
controlled.
|
||||
|
||||
Next, consider the case of too slow link between initiator and target,
|
||||
when the initiator tries to simultaneously push N commands to the target
|
||||
@@ -2330,13 +2352,8 @@ command, hence one or more commands in the tail of the queue can not be
|
||||
served on time less than the timeout, so the initiator will decide that
|
||||
they are stuck on the target and will try to recover.
|
||||
|
||||
To workaround/fix this issue in this case you can use ways 1, 2, 3, 6
|
||||
above or (7): increase speed of the link between target and initiator.
|
||||
But for some initiators implementations for WRITE commands there might
|
||||
be cases when target has no way to detect the issue, so dynamic I/O flow
|
||||
control will not be able to help. In those cases you could also need on
|
||||
the initiator(s) to either decrease the queue depth (way 2), or increase
|
||||
the corresponding timeout (way 3).
|
||||
To workaround/fix this issue in this case you can use ways 1, 2, 3 above
|
||||
or (7): increase speed of the link between target and initiator.
|
||||
|
||||
Note, that logged messages about QUEUE_FULL status are quite different
|
||||
by nature. This is a normal work, just SCSI flow control in action.
|
||||
|
||||
@@ -119,10 +119,12 @@ struct kmem_cache *scst_cmd_cachep;
|
||||
unsigned long scst_trace_flag;
|
||||
#endif
|
||||
|
||||
int scst_max_tasklet_cmd = SCST_DEF_MAX_TASKLET_CMD;
|
||||
|
||||
unsigned long scst_flags;
|
||||
|
||||
unsigned long scst_poll_ns = SCST_DEF_POLL_NS;
|
||||
|
||||
int scst_max_tasklet_cmd = SCST_DEF_MAX_TASKLET_CMD;
|
||||
|
||||
struct scst_cmd_threads scst_main_cmd_threads;
|
||||
|
||||
struct scst_percpu_info scst_percpu_infos[NR_CPUS];
|
||||
|
||||
@@ -184,6 +184,9 @@ extern unsigned int scst_setup_id;
|
||||
#define SCST_DEF_MAX_TASKLET_CMD 10
|
||||
extern int scst_max_tasklet_cmd;
|
||||
|
||||
#define SCST_DEF_POLL_NS 0
|
||||
extern unsigned long scst_poll_ns;
|
||||
|
||||
extern spinlock_t scst_init_lock;
|
||||
extern struct list_head scst_init_cmd_list;
|
||||
extern wait_queue_head_t scst_init_cmd_list_waitQ;
|
||||
|
||||
@@ -7052,6 +7052,53 @@ static struct kobj_attribute scst_max_tasklet_cmd_attr =
|
||||
__ATTR(max_tasklet_cmd, S_IRUGO | S_IWUSR, scst_max_tasklet_cmd_show,
|
||||
scst_max_tasklet_cmd_store);
|
||||
|
||||
static ssize_t scst_poll_us_show(struct kobject *kobj,
|
||||
struct kobj_attribute *attr, char *buf)
|
||||
{
|
||||
int count;
|
||||
unsigned long t = scst_poll_ns;
|
||||
|
||||
TRACE_ENTRY();
|
||||
|
||||
do_div(t, 1000);
|
||||
count = sprintf(buf, "%ld\n%s\n", t,
|
||||
(scst_poll_ns == SCST_DEF_POLL_NS)
|
||||
? "" : SCST_SYSFS_KEY_MARK);
|
||||
|
||||
TRACE_EXIT();
|
||||
return count;
|
||||
}
|
||||
|
||||
static ssize_t scst_poll_us_store(struct kobject *kobj,
|
||||
struct kobj_attribute *attr, const char *buf, size_t count)
|
||||
{
|
||||
int res;
|
||||
unsigned long val;
|
||||
|
||||
TRACE_ENTRY();
|
||||
|
||||
res = kstrtoul(buf, 0, &val);
|
||||
if (res != 0) {
|
||||
PRINT_ERROR("kstrtoul() for %s failed: %d ", buf, res);
|
||||
goto out;
|
||||
}
|
||||
|
||||
PRINT_INFO("Changed poll_us to %ld us", val);
|
||||
|
||||
val *= 1000;
|
||||
scst_poll_ns = val;
|
||||
|
||||
res = count;
|
||||
|
||||
out:
|
||||
TRACE_EXIT_RES(res);
|
||||
return res;
|
||||
}
|
||||
|
||||
static struct kobj_attribute scst_poll_us_attr =
|
||||
__ATTR(poll_us, S_IRUGO | S_IWUSR, scst_poll_us_show,
|
||||
scst_poll_us_store);
|
||||
|
||||
static ssize_t scst_suspend_show(struct kobject *kobj,
|
||||
struct kobj_attribute *attr, char *buf)
|
||||
{
|
||||
@@ -7326,6 +7373,7 @@ static struct attribute *scst_sysfs_root_default_attrs[] = {
|
||||
&scst_threads_attr.attr,
|
||||
&scst_setup_id_attr.attr,
|
||||
&scst_max_tasklet_cmd_attr.attr,
|
||||
&scst_poll_us_attr.attr,
|
||||
&scst_suspend_attr.attr,
|
||||
#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
|
||||
&scst_main_trace_level_attr.attr,
|
||||
|
||||
@@ -5623,6 +5623,38 @@ again:
|
||||
thr_locked = false;
|
||||
}
|
||||
|
||||
if (scst_poll_ns > 0) {
|
||||
struct timespec ts;
|
||||
ktime_t end, kt;
|
||||
int rc;
|
||||
|
||||
rc = __getnstimeofday(&ts);
|
||||
if (unlikely(rc != 0)) {
|
||||
WARN_ON_ONCE(rc);
|
||||
goto go;
|
||||
}
|
||||
|
||||
end = timespec_to_ktime(ts);
|
||||
end = ktime_add_ns(end, scst_poll_ns);
|
||||
|
||||
do {
|
||||
barrier();
|
||||
if (!list_empty(&p_cmd_threads->active_cmd_list) ||
|
||||
!list_empty(&thr->thr_active_cmd_list)) {
|
||||
TRACE_DBG("Poll successful");
|
||||
goto again;
|
||||
}
|
||||
cpu_relax();
|
||||
rc = __getnstimeofday(&ts);
|
||||
if (unlikely(rc != 0)) {
|
||||
WARN_ON_ONCE(rc);
|
||||
goto go;
|
||||
}
|
||||
kt = timespec_to_ktime(ts);
|
||||
} while (ktime_before(kt, end));
|
||||
}
|
||||
|
||||
go:
|
||||
spin_lock_irq(&p_cmd_threads->cmd_list_lock);
|
||||
spin_lock(&thr->thr_cmd_list_lock);
|
||||
}
|
||||
|
||||
@@ -1293,7 +1293,7 @@ Returns: (boolean) $groupExists
|
||||
=item SCST::SCST->addGroup();
|
||||
|
||||
Adds a security group to SCST's configuration. Returns 0 upon success, 1 if
|
||||
unsuccessfull and 2 if the group already exists.
|
||||
unsuccessful and 2 if the group already exists.
|
||||
|
||||
Arguments: (string) $group
|
||||
|
||||
@@ -1302,11 +1302,11 @@ Returns: (int) $success
|
||||
=item SCST::SCST->removeGroup();
|
||||
|
||||
Removes a group from SCST's configuration. Returns 0 upon success, 1 if
|
||||
unsuccessfull and 2 if group does not exist.
|
||||
unsuccessful and 2 if group does not exist.
|
||||
|
||||
=item SCST::SCST->renameGroup();
|
||||
|
||||
Renames an already existing group. Returns 0 upon success, 1 if unsuccessfull
|
||||
Renames an already existing group. Returns 0 upon success, 1 if unsuccessful
|
||||
or 2 if the new group name already exists.
|
||||
|
||||
=item SCST::SCST->sgvStats();
|
||||
@@ -1376,7 +1376,7 @@ Returns: (int) $handler_type
|
||||
=item SCST::SCST->openDevice();
|
||||
|
||||
Opens an already existing specified device for the specified device handler.
|
||||
Returns 0 upon success, 1 if unsuccessfull and 2 if the device already exists.
|
||||
Returns 0 upon success, 1 if unsuccessful and 2 if the device already exists.
|
||||
|
||||
Available options for the parameter $options are: WRITE_THROUGH, READ_ONLY, O_DIRECT
|
||||
|
||||
@@ -1387,7 +1387,7 @@ Returns: (int) $success
|
||||
=item SCST::SCST->closeDevice();
|
||||
|
||||
Closes an open device configured for the specified device handler. Returns
|
||||
0 upon success, 1 if unsuccessfull and 2 of the device does not exist.
|
||||
0 upon success, 1 if unsuccessful and 2 of the device does not exist.
|
||||
|
||||
Arguments: (int) $handler, (string) $device, (string) $path
|
||||
|
||||
@@ -1396,7 +1396,7 @@ Returns: (int) $success
|
||||
=item SCST::SCST->setT10DeviceId();
|
||||
|
||||
Changes the T10 device ID for the specified device and handler. Returns
|
||||
0 upon success, 1 if unsuccessfull and 2 of the device does not exist.
|
||||
0 upon success, 1 if unsuccessful and 2 of the device does not exist.
|
||||
|
||||
Arguments: (int) $handler, (string) $device, (string) $t10_dev_id
|
||||
|
||||
@@ -1421,7 +1421,7 @@ Returns: (hash ref) $users
|
||||
=item SCST::SCST->addUser();
|
||||
|
||||
Adds the specified user to the specified security group. Returns 0
|
||||
upon success, 1 if unsuccessfull and 2 if the user already exists.
|
||||
upon success, 1 if unsuccessful and 2 if the user already exists.
|
||||
|
||||
Arguments: (string) $user, (string) $group
|
||||
|
||||
@@ -1430,7 +1430,7 @@ Returns: (int) $success
|
||||
=item SCST::SCST->removeUser();
|
||||
|
||||
Removed the specified user from the specified security group. Returns
|
||||
0 upon success, 1 if unsuccessfull and 2 if the user does not exist.
|
||||
0 upon success, 1 if unsuccessful and 2 if the user does not exist.
|
||||
|
||||
Arguments: (string) $user, (string) $group
|
||||
|
||||
@@ -1440,7 +1440,7 @@ Returns: (int) $success
|
||||
|
||||
Moves a user from one group to another. Both groups must be defined
|
||||
and user must already exist in the first group. Returns 0 upon
|
||||
success, 1 if unsuccessfull and 2 if the user already exists in the
|
||||
success, 1 if unsuccessful and 2 if the user already exists in the
|
||||
second group.
|
||||
|
||||
Arguments: (string) $user, (string) $fromGroup, (string) $toGroup
|
||||
@@ -1450,7 +1450,7 @@ Returns: (int) $success
|
||||
=item SCST::SCST->clearUsers();
|
||||
|
||||
Removes all users from the specified security group. Returns 0 upon
|
||||
success or 1 if unsuccessfull.
|
||||
success or 1 if unsuccessful.
|
||||
|
||||
Arguments: (string) $group
|
||||
|
||||
@@ -1495,7 +1495,7 @@ Hash Layout: (string) $device = (int) $lun
|
||||
=item SCST::SCST->assignDeviceToGroup();
|
||||
|
||||
Assigns the specified device to the specified security group. Returns
|
||||
0 upon success, 1 if unsuccessfull and 2 if the device has already
|
||||
0 upon success, 1 if unsuccessful and 2 if the device has already
|
||||
been assigned to the specified security group.
|
||||
|
||||
Arguments: (string) $device, (string) $group, (int) $lun [, (string) $options]
|
||||
@@ -1506,7 +1506,7 @@ Returns: (int) $success
|
||||
|
||||
Replaces an already assigned device to the specified lun in a
|
||||
specified security group with $newDevice. Returns 0 upon success, 1
|
||||
if unsuccessfull and 2 if the device has already been assigned to
|
||||
if unsuccessful and 2 if the device has already been assigned to
|
||||
the specified security group.
|
||||
|
||||
Arguments: (string) $newDevice, (string) $group, (int) $lun [, (string) $options]
|
||||
@@ -1516,7 +1516,7 @@ Returns (int) $success
|
||||
=item SCST::SCST->assignDeviceToHandler();
|
||||
|
||||
Assigns specified device to specified handler. Returns 0 upon success,
|
||||
1 if unsuccessfull and 2 if the specified device is already assigned to
|
||||
1 if unsuccessful and 2 if the specified device is already assigned to
|
||||
the specified handler.
|
||||
|
||||
Arguments: (string) $device, (string) $handler
|
||||
@@ -1526,7 +1526,7 @@ Returns: (int) $success
|
||||
=item SCST::SCST->removeDeviceFromGroup();
|
||||
|
||||
Removes the specified device from the specified security group. Returns
|
||||
0 upon success, 1 if unsuccessfull and 2 if the device has not been
|
||||
0 upon success, 1 if unsuccessful and 2 if the device has not been
|
||||
assigned to the specified security group.
|
||||
|
||||
Arguments: (string) $device, (string) $group
|
||||
@@ -1536,7 +1536,7 @@ Returns: (int) $success
|
||||
=item SCST::SCST->clearGroupDevices();
|
||||
|
||||
Removes all devices from the specified security group. Returns 0 upon
|
||||
success or 1 if unsuccessfull.
|
||||
success or 1 if unsuccessful.
|
||||
|
||||
Arguments: (string) $group
|
||||
|
||||
|
||||
Reference in New Issue
Block a user