Messages in this thread | | | Date | Wed, 15 Jun 2005 17:48:42 +0530 | From | Dipankar Sarma <> | Subject | Re: [PATCH 0/6] files: scalable fd management (V4) |
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Hello Andrew,
On Tue, Jun 14, 2005 at 01:03:38PM -0700, Andrew Morton wrote: > Dipankar Sarma <dipankar@in.ibm.com> wrote: > > tiobench on a 4-way ppc64 system : > > (lockfree) > > Test 2.6.10-vanilla Stdev 2.6.10-fd Stdev > > ------------------------------------------------------------- > > Seqread 1428 32.47 1475.0 29.11 > > We don't seem to have gained anything?
I repeated the measurements on ramfs (as opposed to ext2 on ramdisk in the earlier measurement) and I got more consistent results from tiobench :
4(8) way xeon P4 ----------------- (lock-free) Test 2.6.12-rc5 Stdev 2.6.12-rc5-fd Stdev ------------------------------------------------------------- Seqread 1282 18.59 1343.6 26.37 Randread 1517 7 2415 34.27 Seqwrite 702.2 5.27 709.46 5.9 Randwrite 846.86 15.15 919.68 21.4
4-way ppc64 ------------ (lock-free) Test 2.6.12-rc5 Stdev 2.6.12-rc5-fd Stdev ------------------------------------------------------------- Seqread 1549 91.16 1569.6 47.2 Randread 1473.6 25.11 1585.4 69.99 Seqwrite 1096.8 20.03 1136 29.61 Randwrite 1189.6 4.04 1275.2 32.96
Also running Tridge's thread_perf test on ppc64 :
2.6.12-rc5-vanilla -------------------- Running test 'readwrite' with 4 tasks Threads 0.20 +/- 0.02 seconds Processes 0.16 +/- 0.01 seconds
2.6.12-rc5-fd -------------------- Running test 'readwrite' with 4 tasks Threads 0.18 +/- 0.04 seconds Processes 0.16 +/- 0.01 seconds
The benefits are huge (upto ~60%) in some cases on x86 primarily due to the atomic operations during acquisition of ->file_lock and cache line bouncing in fast path. ppc64 benefits are modest due to LL/SC based locking, but still statistically significant.
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