Russell asked me to try some benchmarks on some of the "memset" optimizations
in recent kernels. I thought I'd post them here in case others are
interested.
I ran lmbench (version 2alpha10 as it happens) twice in quick succession on
each kernel. All the kernels were, I hope, identical other than the memset
thing. The machine I used was my CATS.
The "a" kernel is 2.3.19 with Russell's unmodified `memset' macro.
The "b" kernel has the `memset' macro removed from <asm/string.h>, which
should restore things to how they were in older kernels.
The "c" kernel has the slightly modified `memset' macro that is currently
in CVS.
p.
Processor, Processes - times in microseconds - smaller is better
----------------------------------------------------------------
Host OS Mhz null null open selct sig sig fork exec sh
call I/O stat clos inst hndl proc proc proc
--------- ------------- ---- ---- ---- ---- ---- ----- ---- ---- ---- ---- ----
armv4l-li Linux 2.3.19a 233 0.6 1.3 10 12 0.13K 4.7 4 2.9K 11K 49K
armv4l-li Linux 2.3.19a 233 0.6 1.3 9 12 0.13K 4.7 4 2.9K 11K 49K
armv4l-li Linux 2.3.19b 233 0.6 1.3 10 12 0.13K 4.6 4 2.9K 11K 49K
armv4l-li Linux 2.3.19b 233 0.6 1.3 10 12 0.13K 4.6 4 2.9K 11K 49K
armv4l-li Linux 2.3.19c 233 0.6 1.3 10 12 0.13K 4.6 4 2.9K 11K 49K
armv4l-li Linux 2.3.19c 233 0.6 1.3 10 12 0.13K 4.7 4 2.9K 11K 49K
Context switching - times in microseconds - smaller is better
-------------------------------------------------------------
Host OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K
ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw
--------- ------------- ----- ------ ------ ------ ------ ------- -------
armv4l-li Linux 2.3.19a 208 425 912 443 926 454 952
armv4l-li Linux 2.3.19a 210 425 917 443 921 460 934
armv4l-li Linux 2.3.19b 206 420 911 423 918 455 939
armv4l-li Linux 2.3.19b 206 420 915 447 958 446 936
armv4l-li Linux 2.3.19c 212 416 909 423 972 444 959
armv4l-li Linux 2.3.19c 207 419 911 451 918 445 941
*Local* Communication latencies in microseconds - smaller is better
-------------------------------------------------------------------
Host OS 2p/0K Pipe AF UDP RPC/ TCP RPC/ TCP
ctxsw UNIX UDP TCP conn
--------- ------------- ----- ----- ---- ----- ----- ----- ----- ----
armv4l-li Linux 2.3.19a 208 418 1115 764 983 2204
armv4l-li Linux 2.3.19a 210 429 1031 759 986 2188
armv4l-li Linux 2.3.19b 206 417 1147 765 973 2215
armv4l-li Linux 2.3.19b 206 421 1096 761 988 2199
armv4l-li Linux 2.3.19c 212 422 1196 764 983 2207
armv4l-li Linux 2.3.19c 207 428 1027 759 987 2195
File & VM system latencies in microseconds - smaller is better
--------------------------------------------------------------
Host OS 0K File 10K File Mmap Prot Page
Create Delete Create Delete Latency Fault Fault
--------- ------------- ------ ------ ------ ------ ------- ----- -----
armv4l-li Linux 2.3.19a 5053 2 0.0K
armv4l-li Linux 2.3.19a 5017 2 0.0K
armv4l-li Linux 2.3.19b 5022 2 0.0K
armv4l-li Linux 2.3.19b 5055 2 0.0K
armv4l-li Linux 2.3.19c 5009 2 0.0K
armv4l-li Linux 2.3.19c 5013 2 0.0K
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