From: Zoltan Kiss <zoltan.k...@schaman.hu> Date: Fri, 27 Jun 2014 10:01:23 +0100
> On 26/06/14 01:54, David Miller wrote: >> From: Zoltan Kiss <zoltan.k...@citrix.com> >> Date: Tue, 24 Jun 2014 21:40:15 +0100 >> >>> Introduces a new flag called PATTERN, which puts a non-periodic, >>> predicatble >>> pattern into the payload. This was useful to reproduce an otherwise >>> intermittent >>> bug in xen-netback [1], where checksum checking doesn't help. >>> The pattern is a repetition of " %lu", a series of increasing numbers >>> divided by >>> space. The value of the number is the size of the preceding payload >>> area. E.g. >>> " 1 3 5"..." 1000 1005 1010" >>> If the pattern is used, every frag will have its own page, unlike >>> before, so it >>> needs more memory. >>> >>> [1] 5837574: xen-netback: Fix grant ref resolution in RX path >>> >>> Signed-off-by: Zoltan Kiss <zoltan.k...@citrix.com> >> You are changing the page allocation strategy regardless of the >> pattern >> setting, this is undesirable. >> >> It may be significantly faster to use the same page for all the frags, >> and this is absolutely critical for pktgen usage where every >> nanosecond >> of performance counts. > If the PATTERN flag is not used, it always using the pages[0] page, so > it falls back to the original way. That's now what I see. If the size exceeds a page, the current code will use the same page over and over again. Your new code always increments 'i' and allocates a new page, regardless of whether the PATTERN flag is set. Or do I misread your changes? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/