On Thu, Nov 26, 2020 at 2:31 PM Dmitry Antipov <dmantipov@xxxxxxxxx> wrote:
On 11/26/20 12:49 PM, Yaniv Kaul wrote:
> I run a slightly different command, which hides the kernel stuff and focuses on the user mode functions:
> sudo perf record --call-graph dwarf -j any --buildid-all --all-user -p `pgrep -d\, gluster` -F 2000 -ag
Thanks.
BTW, how much is an overhead of passing data between xlators? Even if the most of their features
are disabled, just passing through all of the below is unlikely to have near-to-zero overhead:
Very good question. I was always suspicious of that flow, and I do believe we could do some optimizations, but here's the response I've received back then:
Here's some data from some tests I was running last week - the avg round-trip
time spent by fops in the brick stack from the top translator io-stats till
posix before it is executed on-disk is less than 20 microseconds. And this
stack includes both translators that are enabled and used in RHHI as well as
the do-nothing xls you mention. In contrast, the round-trip time spent by these
fops between the client and server translator is of the order of a few hundred
microseconds to sometimes even 1ms.
time spent by fops in the brick stack from the top translator io-stats till
posix before it is executed on-disk is less than 20 microseconds. And this
stack includes both translators that are enabled and used in RHHI as well as
the do-nothing xls you mention. In contrast, the round-trip time spent by these
fops between the client and server translator is of the order of a few hundred
microseconds to sometimes even 1ms.
Thread 14 (Thread 0x7f2c0e7fc640 (LWP 19482) "glfs_rpcrqhnd"):
#0 data_unref (this=0x7f2bfc032e68) at dict.c:768
#1 0x00007f2c290b90b9 in dict_deln (keylen=<optimized out>, key=0x7f2c163d542e "glusterfs.inodelk-dom-count", this=0x7f2bfc0bb1c8) at dict.c:645
#2 dict_deln (this=0x7f2bfc0bb1c8, key=0x7f2c163d542e "glusterfs.inodelk-dom-count", keylen=<optimized out>) at dict.c:614
#3 0x00007f2c163c87ee in pl_get_xdata_requests (local=0x7f2bfc0ea658, xdata=0x7f2bfc0bb1c8) at posix.c:238
#4 0x00007f2c163b3267 in pl_get_xdata_requests (xdata=0x7f2bfc0bb1c8, local=<optimized out>) at posix.c:213
For example, https://github.com/gluster/glusterfs/issues/1707 optimizes pl_get_xdata_requests() a bit.
Y.
#5 pl_writev (frame=0x7f2bfc0d5348, this=0x7f2c08014830, fd=0x7f2bfc0bc768, vector=0x7f2bfc105478, count=1, offset=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at posix.c:2299
#6 0x00007f2c16395e31 in worm_writev (frame=0x7f2bfc0d5348, this=<optimized out>, fd=0x7f2bfc0bc768, vector=0x7f2bfc105478, count=1, offset=108306432, flags=0, iobref=0x7f2c080820d0,
xdata=0x7f2bfc0bb1c8) at worm.c:429
#7 0x00007f2c1638a55f in ro_writev (frame=frame@entry=0x7f2bfc0d5348, this=<optimized out>, fd=fd@entry=0x7f2bfc0bc768, vector=vector@entry=0x7f2bfc105478, count=count@entry=1,
off=off@entry=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at read-only-common.c:374
#8 0x00007f2c163705ac in leases_writev (frame=frame@entry=0x7f2bfc0bf148, this=0x7f2c0801a230, fd=fd@entry=0x7f2bfc0bc768, vector=vector@entry=0x7f2bfc105478, count=count@entry=1,
off=off@entry=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at leases.c:132
#9 0x00007f2c1634f6a8 in up_writev (frame=0x7f2bfc067508, this=0x7f2c0801bf00, fd=0x7f2bfc0bc768, vector=0x7f2bfc105478, count=1, off=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8)
at upcall.c:124
#10 0x00007f2c2913e6c2 in default_writev (frame=0x7f2bfc067508, this=<optimized out>, fd=0x7f2bfc0bc768, vector=0x7f2bfc105478, count=1, off=108306432, flags=0, iobref=0x7f2c080820d0,
xdata=0x7f2bfc0bb1c8) at defaults.c:2550
#11 0x00007f2c2913e6c2 in default_writev (frame=frame@entry=0x7f2bfc067508, this=<optimized out>, fd=fd@entry=0x7f2bfc0bc768, vector=vector@entry=0x7f2bfc105478, count=count@entry=1,
off=off@entry=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at defaults.c:2550
#12 0x00007f2c16315eb7 in marker_writev (frame=frame@entry=0x7f2bfc119e48, this=this@entry=0x7f2c08021440, fd=fd@entry=0x7f2bfc0bc768, vector=vector@entry=0x7f2bfc105478, count=count@entry=1,
offset=offset@entry=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at marker.c:940
#13 0x00007f2c162fc0ab in barrier_writev (frame=0x7f2bfc119e48, this=<optimized out>, fd=0x7f2bfc0bc768, vector=0x7f2bfc105478, count=1, off=108306432, flags=0, iobref=0x7f2c080820d0,
xdata=0x7f2bfc0bb1c8) at barrier.c:248
#14 0x00007f2c2913e6c2 in default_writev (frame=0x7f2bfc119e48, this=<optimized out>, fd=0x7f2bfc0bc768, vector=0x7f2bfc105478, count=1, off=108306432, flags=0, iobref=0x7f2c080820d0,
xdata=0x7f2bfc0bb1c8) at defaults.c:2550
#15 0x00007f2c162c5cda in quota_writev (frame=frame@entry=0x7f2bfc119e48, this=<optimized out>, fd=fd@entry=0x7f2bfc0bc768, vector=vector@entry=0x7f2bfc105478, count=count@entry=1,
off=off@entry=108306432, flags=0, iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at quota.c:1947
#16 0x00007f2c16299c89 in io_stats_writev (frame=frame@entry=0x7f2bfc0e4358, this=this@entry=0x7f2c08029df0, fd=0x7f2bfc0bc768, vector=vector@entry=0x7f2bfc105478, count=1, offset=108306432, flags=0,
iobref=0x7f2c080820d0, xdata=0x7f2bfc0bb1c8) at io-stats.c:2893
#17 0x00007f2c161f01ac in server4_writev_resume (frame=0x7f2bfc0ef5c8, bound_xl=0x7f2c08029df0) at server-rpc-fops_v2.c:3017
#18 0x00007f2c161f901c in resolve_and_resume (fn=<optimized out>, frame=<optimized out>) at server-resolve.c:680
#19 server4_0_writev (req=<optimized out>) at server-rpc-fops_v2.c:3943
#20 0x00007f2c290696e5 in rpcsvc_request_handler (arg=0x7f2c1614c0b8) at rpcsvc.c:2233
#21 0x00007f2c28ffa3f9 in start_thread (arg=0x7f2c0e7fc640) at pthread_create.c:463
#22 0x00007f2c28f25903 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
Dmitry
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