Messages in this thread | | | Date | Thu, 8 May 2008 11:21:02 +0200 | From | Ingo Molnar <> | Subject | Re: AIM7 40% regression with 2.6.26-rc1 |
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* Zhang, Yanmin <yanmin_zhang@linux.intel.com> wrote:
> > disk_cp /mnt/shm > > disk_cp (1): cannot open /mnt/shm/tmpa.common > > disk1.c: No such file or directory > > > > [.. etc. a large stream of them .. ] > > > > system has 2GB of RAM and tmpfs mounted to the place where aim7 puts its > > work files.
> My machine has 8GB. To simulate your environment, I reserve 6GB for > hugetlb, then reran the testing and didn't see any failure except: AIM > Multiuser Benchmark - Suite VII Run Beginning > > Tasks jobs/min jti jobs/min/task real cpu > 2000create_shared_memory(): can't create semaphore, pausing... > create_shared_memory(): can't create semaphore, pausing...
that failure message you got worries me - it indicates that your test ran out of IPC semaphores. You can fix it via upping the semaphore limits via:
echo "500 32000 128 512" > /proc/sys/kernel/sem
could you check that you still get similar results with this limit fixed?
note that once i've fixed the semaphore limits it started running fine here. And i see zero idle time during the run on a quad core box.
here are my numbers:
# on v2.6.26-rc1-166-gc0a1811
Tasks Jobs/Min JTI Real CPU Jobs/sec/task 2000 55851.4 93 208.4 793.6 0.4654 # BKL: sleep 2000 55402.2 79 210.1 800.1 0.4617
2000 55728.4 93 208.9 795.5 0.4644 # BKL: spin 2000 55787.2 93 208.7 794.5 0.4649 #
so the results are the same within noise.
I'll also check this workload on an 8-way box to make sure it's OK on larger CPU counts too.
could you double-check your test?
plus a tty tidbit as well, during the test i saw a few of these:
Warning: dev (tty1) tty->count(639) != #fd's(638) in release_dev Warning: dev (tty1) tty->count(462) != #fd's(463) in release_dev Warning: dev (tty1) tty->count(274) != #fd's(275) in release_dev Warning: dev (tty1) tty->count(4) != #fd's(3) in release_dev Warning: dev (tty1) tty->count(164) != #fd's(163) in release_dev
Ingo
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