03-30-2010
Quote:
Originally Posted by
binlib
If you make it sleep shorter time or make your machine busier, you will observe your original problem with named pipe (or any other methods). A Unix pipe has at least 4k buffer size and I don't think there is a way to make it smaller. Without a way to reduce the pipe size and not able to modify the streaming code, I see no way to solve your problem.
If you're saying that the loop may run a few more times, sure. You are quite correct. The generator will write a few bytes into the pipe's buffer, never filling the buffer, and will loop until its timeslice is exhausted. But a few extra loop iterations is not the same as his original problem, in which the generator would run without end.
Regards,
Alister
Last edited by alister; 03-30-2010 at 02:01 AM..
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LEARN ABOUT CENTOS
perf-bench
PERF-BENCH(1) perf Manual PERF-BENCH(1)
NAME
perf-bench - General framework for benchmark suites
SYNOPSIS
perf bench [<common options>] <subsystem> <suite> [<options>]
DESCRIPTION
This perf bench command is a general framework for benchmark suites.
COMMON OPTIONS
-f, --format=
Specify format style. Current available format styles are:
default
Default style. This is mainly for human reading.
.ft C
% perf bench sched pipe # with no style specified
(executing 1000000 pipe operations between two tasks)
Total time:5.855 sec
5.855061 usecs/op
170792 ops/sec
.ft
simple
This simple style is friendly for automated processing by scripts.
.ft C
% perf bench --format=simple sched pipe # specified simple
5.988
.ft
SUBSYSTEM
sched
Scheduler and IPC mechanisms.
mem
Memory access performance.
all
All benchmark subsystems.
SUITES FOR sched
messaging
Suite for evaluating performance of scheduler and IPC mechanisms. Based on hackbench by Rusty Russell.
Options of messaging
-p, --pipe
Use pipe() instead of socketpair()
-t, --thread
Be multi thread instead of multi process
-g, --group=
Specify number of groups
-l, --loop=
Specify number of loops
Example of messaging
.ft C
% perf bench sched messaging # run with default
options (20 sender and receiver processes per group)
(10 groups == 400 processes run)
Total time:0.308 sec
% perf bench sched messaging -t -g 20 # be multi-thread, with 20 groups
(20 sender and receiver threads per group)
(20 groups == 800 threads run)
Total time:0.582 sec
.ft
pipe
Suite for pipe() system call. Based on pipe-test-1m.c by Ingo Molnar.
Options of pipe
-l, --loop=
Specify number of loops.
Example of pipe
.ft C
% perf bench sched pipe
(executing 1000000 pipe operations between two tasks)
Total time:8.091 sec
8.091833 usecs/op
123581 ops/sec
% perf bench sched pipe -l 1000 # loop 1000
(executing 1000 pipe operations between two tasks)
Total time:0.016 sec
16.948000 usecs/op
59004 ops/sec
.ft
SUITES FOR mem
memcpy
Suite for evaluating performance of simple memory copy in various ways.
Options of memcpy
-l, --length
Specify length of memory to copy (default: 1MB). Available units are B, KB, MB, GB and TB (case insensitive).
-r, --routine
Specify routine to copy (default: default). Available routines are depend on the architecture. On x86-64, x86-64-unrolled,
x86-64-movsq and x86-64-movsb are supported.
-i, --iterations
Repeat memcpy invocation this number of times.
-c, --cycle
Use perf's cpu-cycles event instead of gettimeofday syscall.
-o, --only-prefault
Show only the result with page faults before memcpy.
-n, --no-prefault
Show only the result without page faults before memcpy.
memset
Suite for evaluating performance of simple memory set in various ways.
Options of memset
-l, --length
Specify length of memory to set (default: 1MB). Available units are B, KB, MB, GB and TB (case insensitive).
-r, --routine
Specify routine to set (default: default). Available routines are depend on the architecture. On x86-64, x86-64-unrolled,
x86-64-stosq and x86-64-stosb are supported.
-i, --iterations
Repeat memset invocation this number of times.
-c, --cycle
Use perf's cpu-cycles event instead of gettimeofday syscall.
-o, --only-prefault
Show only the result with page faults before memset.
-n, --no-prefault
Show only the result without page faults before memset.
SEE ALSO
perf(1)
perf 06/30/2014 PERF-BENCH(1)