[ruby-core:91161] Re: Testing MJIT on RHEL 7.5

> On Jan 18, 2019, at 1:31 PM, Phil Edelbrock <[e-mail]> wrote:
> 
> 
> 
>> On Jan 18, 2019, at 8:22 AM, Takashi Kokubun <[e-mail]> wrote:
>> 
>> Hi,
>> 
>>> time /usr/local/ruby-edge/bin/ruby --disable-gems --jit -e "5000000.times { 3 * 123 }"
>>> real    0m0.229s
>> 
>> 229ms is too short to measure JIT-ed code's performance. Because of this:
>> 
>> $ time ./ruby --disable-gems -e ""
>> ./ruby --disable-gems -e ""  0.00s user 0.00s system 95% cpu 0.005 total
>> $ time ./ruby --disable-gems --jit -e ""
>> ./ruby --disable-gems --jit -e ""  0.12s user 0.02s system 100% cpu 0.135 total
>> 
>> large amount of time you measure would be just time consumed for
>> stopping JIT thread.
>> This behavior is limitation of JIT-ing by invoking C compiler, and
>> this is something intentional for now.
>> 
>> Due to that, what we can do for now is just like (this is ruby 2.6.0
>> x86_64-linux):
>> 
>> $ time ./ruby --disable-gems -e "500000000.times { 3 * 123 }"
>> ./ruby --disable-gems -e "500000000.times { 3 * 123 }"  13.24s user
>> 0.00s system 99% cpu 13.242 total
>> $ time ./ruby --disable-gems --jit -e "500000000.times { 3 * 123 }"
>> ./ruby --disable-gems --jit -e "500000000.times { 3 * 123 }"  10.13s
>> user 0.02s system 101% cpu 9.989 total
>> 
>> Best,
>> k0kubun
>> 
>> 2019年1月18日(金) 10:34 Phil Edelbrock <[e-mail]>:
>>> 
>>> 
>>> Hello, I'm new to this list.  I hope this is the right place to ask questions about the new experimental JIT implementation (which looks incredibly cool).
>>> 
>>> First, I've got both 2.6.0 installed and the latest from github (which I call 'edge') on RHEL 7.5:
>>> 
>>> [pedelbro@966629-app3 ~]$ /usr/local/ruby-2.6.0/bin/ruby -v
>>> ruby 2.6.0p0 (2018-12-25 revision 66547) [x86_64-linux]
>>> [pedelbro@966629-app3 ~]$ /usr/local/ruby-edge/bin/ruby -v
>>> ruby 2.7.0dev (2019-01-16 trunk 66836) [x86_64-linux]
>>> 
>>> gcc:
>>> 
>>> Thread model: posix
>>> gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC)
>>> 
>>> My /tmp is mounted (by default) as NOEXEC, so I created a regular directory in my home directory to get around the permissions error/warning:
>>> 
>>> MJIT warning: failure in loading code from '/tmp/_ruby_mjit_p108878u0.so': /tmp/_ruby_mjit_p108878u0.so: failed to map segment from shared object: Operation not permitted
>>> 
>>> So, now things seem better:
>>> 
>>> MJIT: CC defaults to /usr/bin/gcc
>>> MJIT: tmp_dir is /home/pedelbro/my_tmp
>>> Creating precompiled header
>>> Starting process: /usr/bin/gcc /usr/bin/gcc -std=gnu99 -w -Wfatal-errors -fPIC -shared -w -pipe -O3 -nodefaultlibs -nostdlib -o /home/pedelbro/my_tmp/_ruby_mjit_hp116911u0.h.gch /usr/local/ruby-edge/include/ruby-2.7.0/x86_64-linux/rb_mjit_min_header-2.7.0.h
>>> start compilation: block in <main>@-e:1 -> /home/pedelbro/my_tmp/_ruby_mjit_p116911u0.c
>>> Starting process: /usr/bin/gcc /usr/bin/gcc -std=gnu99 -w -Wfatal-errors -fPIC -shared -w -pipe -O3 -o /home/pedelbro/my_tmp/_ruby_mjit_p116911u0.o /home/pedelbro/my_tmp/_ruby_mjit_p116911u0.c -c -lgcc -Wl,--compress-debug-sections=zlib -nostartfiles -nodefaultlibs -nostdlib
>>> Starting process: /usr/bin/gcc /usr/bin/gcc -std=gnu99 -shared -Wfatal-errors -fPIC -shared -w -pipe -O3 -o /home/pedelbro/my_tmp/_ruby_mjit_p116911u0.so /home/pedelbro/my_tmp/_ruby_mjit_p116911u0.o -lgcc -Wl,--compress-debug-sections=zlib -nostartfiles -nodefaultlibs -nostdlib
>>> JIT success (37.9ms): block in <main>@-e:1 -> /home/pedelbro/my_tmp/_ruby_mjit_p116911u0.c
>>> 
>>> When testing, though, I only see slowdowns when turning on JIT?
>>> 
>>> This is a simple (and maybe a bad) example:
>>> 
>>> [pedelbro@966629-app3 models]$ time /usr/local/ruby-edge/bin/ruby --disable-gems --jit -e "5000000.times { 3 * 123 }"
>>> 
>>> real    0m0.229s
>>> user    0m0.383s
>>> sys     0m0.049s
>>> [pedelbro@966629-app3 models]$ time /usr/local/ruby-edge/bin/ruby --disable-gems -e "5000000.times { 3 * 123 }"
>>> 
>>> real    0m0.208s
>>> user    0m0.203s
>>> sys     0m0.004s
>>> 
>>> Thanks!  Let me know if this is the wrong list to discuss this.  I hope to be another datapoint for testing, if it helps. :')
>>> 
>>> 
>>> Phil
>>> 
>>> Unsubscribe: <mailto:[e-mail]?subject=unsubscribe>
>>> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>
> 
> 
> Hello Takashi!  It is an honor to chat with you. I love your work. :')
> 
> OK, so here's my output of your examples on both 2.6.0 and a semi-current edge.  What am I doing wrong?  What more info can I provide?
> 
> 
> [pedelbro@966629-app3 bin]$ time ./ruby --disable-gems -e "500000000.times { 3 * 123 }"
> 
> real	0m19.632s
> user	0m19.582s
> sys	0m0.003s
> [pedelbro@966629-app3 bin]$ time ./ruby --disable-gems --jit -e "500000000.times { 3 * 123 }"
> 
> real	0m20.480s
> user	0m20.588s
> sys	0m0.058s
> [pedelbro@966629-app3 bin]$ ./ruby -v
> ruby 2.7.0dev (2019-01-16 trunk 66836) [x86_64-linux]
> 
> 
> [pedelbro@966629-app3 bin]$ cd /usr/local/ruby-2.6.0/bin
> 
> [pedelbro@966629-app3 bin]$ time ./ruby --disable-gems -e "500000000.times { 3 * 123 }"
> 
> real	0m19.351s
> user	0m19.300s
> sys	0m0.005s
> [pedelbro@966629-app3 bin]$ time ./ruby --disable-gems --jit -e "500000000.times { 3 * 123 }"
> 
> real	0m19.821s
> user	0m19.899s
> sys	0m0.061s
> [pedelbro@966629-app3 bin]$ ./ruby -v
> ruby 2.6.0p0 (2018-12-25 revision 66547) [x86_64-linux]
> 
> 
> Phil


I'm sorry, I got tripped up again by the NOEXEC on my /tmp.  Here's a better example and I do see improvement. (btw- I like how it falls back to regular ruby if JIT fails)

[pedelbro@966629-app3 bin]$ mount | grep /tmp
/dev/mapper/vglocal20180828-tmp00 on /tmp type ext4 (rw,nosuid,nodev,noexec,relatime,seclabel,stripe=64,data=ordered)

[pedelbro@966629-app3 ~]$ export TMPDIR=~/my_tmp

[pedelbro@966629-app3 bin]$ time ./ruby --disable-gems --jit -e "500000000.times { 3 * 123 }"

real	0m14.156s
user	0m14.265s
sys	0m0.050s
[pedelbro@966629-app3 bin]$ time ./ruby --disable-gems -e "500000000.times { 3 * 123 }"

real	0m18.465s
user	0m18.417s
sys	0m0.004s

[pedelbro@966629-app3 bin]$ ./ruby -v
ruby 2.7.0dev (2019-01-16 trunk 66836) [x86_64-linux]


Phil


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