The IO performance test with fio after removing the likely and
unlikely macros in all if-statement shows no performance drop.
They do not help for the performance of rnbd.
The fio test did random read on 32 rnbd devices and 64 processes.
Test environment:
- AMD Opteron(tm) Processor 6386 SE
- 125G memory
- kernel version: 5.4.86
- gcc version: gcc (Debian 8.3.0-6) 8.3.0
- Infiniband controller: InfiniBand: Mellanox Technologies MT26428
[ConnectX VPI PCIe 2.0 5GT/s - IB QDR / 10GigE] (rev b0)
before
read: IOPS=549k, BW=2146MiB/s
read: IOPS=544k, BW=2125MiB/s
read: IOPS=553k, BW=2158MiB/s
read: IOPS=535k, BW=2089MiB/s
read: IOPS=543k, BW=2122MiB/s
read: IOPS=552k, BW=2154MiB/s
average: IOPS=546k, BW=2132MiB/s
after
read: IOPS=556k, BW=2172MiB/s
read: IOPS=561k, BW=2191MiB/s
read: IOPS=552k, BW=2156MiB/s
read: IOPS=551k, BW=2154MiB/s
read: IOPS=562k, BW=2194MiB/s
-----------
average: IOPS=556k, BW=2173MiB/s
The IOPS and bandwidth got better slightly after removing
likely/unlikely. (IOPS= +1.8% BW= +1.9%) But we cannot make sure
that removing the likely/unlikely help the performance because it
depends on various situations. We only make sure that removing the
likely/unlikely does not drop the performance.
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Link: https://lore.kernel.org/r/20210428061359.206794-5-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We changed the rnbd_srv_sess_dev_force_close to use try-lock
because rnbd_srv_sess_dev_force_close and process_msg_close
can generate a deadlock.
Now rnbd_srv_sess_dev_force_close would do nothing
if it fails to get the lock. So removing the force_close
file should be moved to after the lock. Or the force_close
file is removed but the others are not removed.
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-11-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The rnbd-client always sets the write-back cache and fua attributes
of the rnbd device queue regardless of the target device on the server.
That generates IO hang issue when the target device does not
support both of write-back cacne and fua.
This patch adds more fields for the cache policy and fua into the
device opening message. The rnbd-server sends the information
if the target device supports the write-back cache and fua
and rnbd-client recevives it and set the device queue accordingly.
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
[jwang: some minor change, rename a few varables, remove unrelated comments.]
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since the removal of the session sysfs can also be called from the
function destroy_sess, there is a need to protect the call from the
function rnbd_srv_sess_dev_force_close
Fixes: 786998050c ("block/rnbd-srv: close a mapped device from server side.")
Signed-off-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Reviewed-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The forceful close of an exported device is required
for the use case, when the client side hangs, is crashed,
or is not accessible.
There have been cases observed, where only some of
the devices are to be cleaned up, but the session shall
remain.
When the device is to be exported to a different
client host, server side cleanup is required.
Signed-off-by: Lutz Pogrell <lutz.pogrell@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Clang warns:
drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
uninitialized whenever 'if' condition is true
[-Wsometimes-uninitialized]
if (IS_ERR(bio)) {
^~~~~~~~~~~
drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
return err;
^~~
drivers/block/rnbd/rnbd-srv.c:150:2: note: remove the 'if' if its
condition is always false
if (IS_ERR(bio)) {
^~~~~~~~~~~~~~~~~~
drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
to silence this warning
int err;
^
= 0
1 warning generated.
err is indeed uninitialized when this statement is taken. Ensure that it
is assigned the error value of bio before jumping to the error handling
label.
Fixes: 735d77d4fd ("rnbd: remove rnbd_dev_submit_io")
Reported-by: Brooke Basile <brookebasile@gmail.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1134
Signed-off-by: Jens Axboe <axboe@kernel.dk>
