[RFC/PATCH, 1/4] readX_check() performance evaluation
From: Hironobu Ishii
Date: Tue Jan 27 2004 - 20:58:48 EST
Hi all,
We are planning recovery from the PCI bus intermittent errors.
PCI-X standard describes it as "5.4 Error Handling and Fault
Tolerance" in PCI-X 1.0b. There were several discussions in lkml,
how to recover from PCI errors.
Seto posted "[RFC] How drivers notice a HW error?" (readX_check() I/F)
http://marc.theaimsgroup.com/?l=linux-kernel&m=106992207709400&w=2
Grant will show his idea near future,
http://marc.theaimsgroup.com/?l=linux-kernel&m=107453681120603&w=2
I made a readX_check() prototype which Seto proposed to measure
performance disadvantage of this kind of I/F. And I made a performance
evaluation of Disk I/O with this prototype.
Comments are welcome.
Conclusion:
Performance disadvantage of readX_check() is a very small.
I'd like you to understand that such a function will not
cause severe performance disadvantage as you imagine.
This patch:
- is for Fusion MPT driver.
- has no error recovery code yet, sorry.
- currently supports ia64 only. But I believe that
some other CPU(such as SPARC, PPC, PA-RISC) can also
support this kind of I/F.
I know, unfortunately, that i386 can't support this kind
of I/F, because it can't recover from machine check state.
How to use this patch:
- Apply to vanilla 2.6.1.
- Rename drivers/message/fusion/mptbase.c to mptbase_main.c
(Because we make mptbase.ko from mptbase.c and read_check.S,
so source file name has to be renamed. Though I know
read_check.S should go under the architecture directory,
because this patch is only for performance evaluation,
forgive me. )
Evaluation Environment:
Kernel:
vanilla 2.6.1 and 2.6.1+readX_check patch
Platform: Intel Tiger-4 (1-CPU)
processor : 0
vendor : GenuineIntel
arch : IA-64
family : Itanium 2
model : 1
revision : 5
archrev : 0
features : branchlong
cpu number : 0
cpu regs : 4
cpu MHz : 1296.473997
itc MHz : 1296.473997
BogoMIPS : 1941.96
SCSI HBA/driver:
onboard LSI Logic 53C1030(FwRev=01030600h, MaxQ=255)
Fusion MPT driver(kernel 2.6.1)
Disks
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: FUJITSU Model: MAP3367NC Rev: 5207
Type: Direct-Access ANSI SCSI revision: 03
Host: scsi0 Channel: 00 Id: 01 Lun: 00
Vendor: FUJITSU Model: MAP3367NC Rev: 5207
Type: Direct-Access ANSI SCSI revision: 03
Host: scsi0 Channel: 00 Id: 02 Lun: 00
Vendor: FUJITSU Model: MAP3367NC Rev: 5207
Type: Direct-Access ANSI SCSI revision: 03
Test tool:
rawread 1.0.3
http://www-124.ibm.com/developerworks/opensource/linuxperf/rawread/rawread.html
Results:
To avoid buffer cache, we measured performance by O_DIRECT.
1-1) ./rawread -p 1 -d 1 -s 512 -n 131072 -x -z
(1 disk, 512-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 5.245 10741 16.2
vanilla 2.6.1 5.269 10790 15.7
---------------------------------------------------
patched/vanilla 0.995 1.032
1-2) ./rawread -p 2 -d 1 -s 512 -n 131072 -x -z
(2 disks, 512-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 10.473 21448 30.6
vanilla 2.6.1 10.548 21602 30.6
---------------------------------------------------
patched/vanilla 0.993 1.000
1-3) ./rawread -p 3 -d 1 -s 512 -n 131072 -x -z
(3 disks, 512-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 11.267 23074 29.9
vanilla 2.6.1 11.251 23042 30.5
---------------------------------------------------
patched/vanilla 1.001 0.980
2-1) ./rawread -p 1 -d 1 -s 4096 -n 131072 -x -z
(1 disk, 4096-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 39.422 10092 14.1
vanilla 2.6.1 39.389 10083 14.0
---------------------------------------------------
patched/vanilla 1.001 1.007
2-2) ./rawread -p 2 -d 1 -s 4096 -n 131072 -x -z
(2 disks, 4096-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 70.438 18032 24.1
vanilla 2.6.1 70.390 18019 24.1
---------------------------------------------------
patched/vanilla 1.001 1.000
2-3) ./rawread -p 3 -d 1 -s 4096 -n 131072 -x -z
(3 disks, 4096-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 70.588 18070 24.5
vanilla 2.6.1 70.861 18140 24.4
---------------------------------------------------
patched/vanilla 0.996 1.004
3-1) ./rawread -p 1 -d 1 -s 32768 -n 131072 -x -z
(1 disk, 32768-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 69.226 2215 3.5
vanilla 2.6.1 68.546 2190 3.4
---------------------------------------------------
patched/vanilla 1.010 1.029
3-2) ./rawread -p 2 -d 1 -s 32768 -n 131072 -x -z
(2 disk, 32768-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 139.315 4458 7.0
vanilla 2.6.1 139.188 4454 6.6
---------------------------------------------------
patched/vanilla 1.010 1.029
3-3) ./rawread -p 3 -d 1 -s 32768 -n 131072 -x -z
(3 disks, 32768-bytes/1-read,)
avg. sys(%)
MB/s IOPS of vmstat
---------------------------------------------------
patched 2.6.1 208.883 6684 10.0
vanilla 2.6.1 209.193 6694 10.2
---------------------------------------------------
patched/vanilla 0.999 0.980
-------
Thanks,
Hironobu Ishii
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/