Commit:     0ccfe61803ad24f1c0fe5e1f5ce840ff0f3d9660
Parent:     e08a132b0ef3cf89dfbf1dea2c6248ea624bdcd7
Author:     Jean Delvare <[EMAIL PROTECTED]>
AuthorDate: Tue Oct 30 00:59:25 2007 -0700
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Tue Oct 30 00:59:25 2007 -0700

    [TCP]: Saner thash_entries default with much memory.
    On systems with a very large amount of memory, the heuristics in
    alloc_large_system_hash() result in a very large TCP established hash
    table: 16 millions of entries for a 128 GB ia64 system. This makes
    reading from /proc/net/tcp pretty slow (well over a second) and as a
    result netstat is slow on these machines. I know that /proc/net/tcp is
    deprecated in favor of tcp_diag, however at the moment netstat only
    knows of the former.
    I am skeptical that such a large TCP established hash is often needed.
    Just because a system has a lot of memory doesn't imply that it will
    have several millions of concurrent TCP connections. Thus I believe
    that we should put an arbitrary high limit to the size of the TCP
    established hash by default. Users who really need a bigger hash can
    always use the thash_entries boot parameter to get more.
    I propose 2 millions of entries as the arbitrary high limit. This
    makes /proc/net/tcp reasonably fast on the system in question (0.2 s)
    while being still large enough for me to be confident that network
    performance won't suffer.
    This is just one way to limit the hash size, there are others; I am not
    familiar enough with the TCP code to decide which is best. Thus, I
    would welcome the proposals of alternatives.
    [ 2 million is still too large, thus I've modified the limit in the
      change to be '512 * 1024'. -DaveM ]
    Signed-off-by: Jean Delvare <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
 net/ipv4/tcp.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2e6ad6d..c64072b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2453,7 +2453,7 @@ void __init tcp_init(void)
-                                       0);
+                                       thash_entries ? 0 : 512 * 1024);
        tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
        for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at

Reply via email to