Commit Graph

7 Commits

Author SHA1 Message Date
Kaike Wan
bcad29137a IB/hfi1: Serve the most starved iowait entry first
When an egress resource(SDMA descriptors, pio credits) is not available,
a sending thread will be put on the resource's wait queue. When the
resource becomes available again, up to a fixed number of sending threads
can be awakened sequentially and removed from the wait queue, depending
on the number of waiting threads and the number of free resources. Since
each awakened sending thread will send as many packets as possible, it
is highly likely that the first sending thread will consume all the
egress resources. Subsequently, it will be put back to the end of the wait
queue. Depending on the timing when the later sending threads wake up,
they may not be able to send any packet and be again put back to the end
of the wait queue sequentially, right behind the first sending thread.
This starvation cycle continues until some sending threads exceed their
retry limit and consequently fail.

This patch fixes the issue by two simple approaches:
(1) Any starved sending thread will be put to the head of the wait queue
while a served sending thread will be put to the tail;
(2) The most starved sending thread will be served first.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-07-31 15:17:54 -04:00
Ira Weiny
e8ea95af87 IB/hfi: Fix up comments in engine mapping
Fix off by 1 error in comments documenting the sdma and send context
mappings.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-04-25 15:24:51 -04:00
Mike Marciniszyn
63df8e09e1 IB/hfi1: Inline sdma_txclean() for verbs pio
Short circuit sdma_txclean() by adding an __sdma_txclean()
that is only called when the tx has sdma mappings.

Convert internal calls to __sdma_txclean().

This removes a call from the critical path.

Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-11-15 16:25:59 -05:00
Tadeusz Struk
af3674d62d IB/hfi1: Add new debugfs sdma_cpu_list file
Add a debugfs sdma_cpu_list file that can be used to examine the CPU to
sdma engine assignments for the whole device.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Reviewed-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-10-02 08:42:19 -04:00
Tadeusz Struk
0cb2aa690c IB/hfi1: Add sysfs interface for affinity setup
Some users want more control over which cpu cores are being used by the
driver. For example, users might want to restrict the driver to some
specified subset of the cores so that they can appropriately partition
processes, irq handlers, and work threads.
To allow the user to fine tune system affinity settings new sysfs
attributes are introduced per sdma engine.  This patch adds a new
attribute type for sdma engine and a new cpu_list attribute.
When the user writes a cpu range to the cpu_list attribute the driver
will create an internal cpu->sdma map, which will be used later as a
look-up table to choose an optimal engine for a user requests.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Reviewed-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-10-02 08:42:17 -04:00
Harish Chegondi
0b115ef100 IB/hfi1: Fix the count of user packets submitted to an SDMA engine
Each user SDMA request coming into the driver may contain multiple packets.
Each user packet may use multiple SDMA descriptors to fill the send buffer.
The field seqsubmitted in struct user_sdma_request counts the number of
user packets submitted to an SDMA engine. Sometimes, the intermediate count
may not be updated properly. However, once all the packets' descriptors
are successfully submitted to the SDMA engine, the final count is updated
correctly. But, if only some of the packets are submitted to the engine due
to an error, the intermediate count doesn't reflect the partial number of
packets submitted to the SDMA engine. This can cause a hang later in the
code as the count of packets submitted to the SDMA engine doesn't match the
the count of packets processed by the SDMA engine.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-10-02 08:42:07 -04:00
Dennis Dalessandro
f48ad614c1 IB/hfi1: Move driver out of staging
The TODO list for the hfi1 driver was completed during 4.6. In addition
other objections raised (which are far beyond what was in the TODO list)
have been addressed as well. It is now time to remove the driver from
staging and into the drivers/infiniband sub-tree.

Reviewed-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-05-26 11:35:14 -04:00