On Thu, Jun 28, 2018 at 9:40 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Thu, 28 Jun 2018 20:29:07 +0200 Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > >> >> Slab memory usage after boot [2]: >> >> * ~40 kb for clean kernel >> >> * ~105 kb + 1/8th shadow ~= 118 kb for KASAN >> >> * ~47 kb + 1/16th shadow ~= 50 kb for KHWASAN >> >> >> >> Network performance [3]: >> >> * 8.33 Gbits/sec for clean kernel >> >> * 3.17 Gbits/sec for KASAN >> >> * 2.85 Gbits/sec for KHWASAN >> >> >> >> Note, that KHWASAN (compared to KASAN) doesn't require quarantine. >> >> >> >> [1] Time before the ext4 driver is initialized. >> >> [2] Measured as `cat /proc/meminfo | grep Slab`. >> >> [3] Measured as `iperf -s & iperf -c 127.0.0.1 -t 30`. >> > >> > The above doesn't actually demonstrate the whole point of the >> > patchset: to reduce KASAN's very high memory consumption? >> >> You mean that memory usage numbers collected after boot don't give a >> representative picture of actual memory consumption on real workloads? >> >> What kind of memory consumption testing would you like to see? > > Well, 100kb or so is a teeny amount on virtually any machine. I'm > assuming the savings are (much) more significant once the machine gets > loaded up and doing work? So with clean kernel after boot we get 40 kb memory usage. With KASAN it is ~120 kb, which is 200% overhead. With KHWASAN it's 50 kb, which is 25% overhead. This should approximately scale to any amounts of used slab memory. For example with 100 mb memory usage we would get +200 mb for KASAN and +25 mb with KHWASAN. (And KASAN also requires quarantine for better use-after-free detection). I can explicitly mention the overhead in %s in the changelog. If you think it makes sense, I can also make separate measurements with some workload. What kind of workload should I use?
