flag: direct use direct I/O for data can be useful too On Wed, Jun 30, 2010 at 12:23 PM, Roman Mamedov <roman@xxxxxxxx> wrote: > On Wed, 30 Jun 2010 08:58:28 +0200 (CEST) > Mikael Abrahamsson <swmike@xxxxxxxxx> wrote: > >> On Wed, 30 Jun 2010, Roman Mamedov wrote: >> >> > This is not necessary. See the dd man page about the conv=fdatasync switch. >> > You can even test with just 256 MB this way, and still get an extremely >> > accurate result. >> >> You're right, for writing this is ok. For read tests it's important to use >> more than ram though, to avoid doing performance testing from block cache >> instead of from the actual drives. > > Yeah, though there's also an alternative way of mitigating the effect of > the cache when testing read speed, see http://linux-mm.org/Drop_Caches > > -- > With respect, > Roman > -- Best regards, [COOLCOLD-RIPN] -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
