Ingo Molnar wrote:
> could someone with a PPro give this patch a try? Maybe it shows up in some
> of the lmbench numbers [lat_proc?].
Here are the lmbench numbers for two tries each of a plain 2.1.50
and one with your patch. The only significant difference I can
find is the longer execution time for a /bin/sh process.
UDP latency is slightly higher, while TCP latency is slightly
lower.
Platform is a PPro 200 MHz with 256 KB cache and 32 MB of parity RAM.
The PPro does cache allocations on write misses, so this probably
outweighs the benefits of not polluting the cache.
Jens.
Processor, Processes - times in microseconds
--------------------------------------------
Host OS Mhz Null Null Simple /bin/sh Mmap 2-proc
8-proc
Syscall Process Process Process lat
ctxsw ctxsw
--------- ------------- ---- ------- ------- ------- ------- ---- ------
------
mingo.1 Linux 2.1.50 200 2 0K 4K 19K 23
4 5
mingo.2 Linux 2.1.50 200 2 0K 4K 19K 26
4 5
2.1.50.1 Linux 2.1.50 200 1 0K 3K 14K 22
4 5
2.1.50.2 Linux 2.1.50 200 1 0K 3K 14K 22
4 5
*Local* Communication latencies in microseconds
-----------------------------------------------
Host OS Pipe UDP RPC/ TCP RPC/
UDP TCP
--------- ------------- ------- ------- ------- ------- -------
mingo.1 Linux 2.1.50 19 65 139 97 213
mingo.2 Linux 2.1.50 18 65 140 96 210
2.1.50.1 Linux 2.1.50 18 63 139 99 211
2.1.50.2 Linux 2.1.50 18 63 138 99 207
*Local* Communication bandwidths in megabytes/second
----------------------------------------------------
Host OS Pipe TCP File Mmap Bcopy Bcopy Mem Mem
reread reread (libc) (hand) read write
--------- ------------- ---- ---- ------ ------ ------ ------ ---- -----
mingo.1 Linux 2.1.50 117 31 51 139 44 37 164 62
mingo.2 Linux 2.1.50 117 30 82 138 44 36 164 62
2.1.50.1 Linux 2.1.50 118 28 93 137 44 36 164 62
2.1.50.2 Linux 2.1.50 118 31 52 137 44 37 164 62
Memory latencies in nanoseconds
(WARNING - may not be correct, check graphs)
--------------------------------------------
Host OS Mhz L1 $ L2 $ Main mem Guesses
--------- ------------- --- ---- ---- -------- -------
mingo.1 Linux 2.1.50 200 10 55 195
mingo.2 Linux 2.1.50 200 10 55 195
2.1.50.1 Linux 2.1.50 200 10 81 195
2.1.50.2 Linux 2.1.50 200 10 30 195