On Wed, Oct 1, 2008 at 12:07 PM, Sridhar Samudrala <sri@xxxxxxxxxx> wrote: > > On Wed, 2008-10-01 at 11:05 -0700, Pranav Desai wrote: >> On Wed, Oct 1, 2008 at 10:28 AM, Sridhar Samudrala <sri@xxxxxxxxxx> wrote: >> > >> > On Wed, 2008-10-01 at 16:55 +0300, Pekka Savola wrote: >> > > On Wed, 1 Oct 2008, Vitaly Ivanov wrote: >> > > > We have solved this problem. We had tuned TCP/IP stack in Linux Kernel >> > > > but it hadn't helped us because there was very law value backlog in >> > > > listen function >> > > > int listen(int sockfd, int backlog); >> > > > This function is used in nginx and lighttp demons. In nginx this value >> > > > had been set to 511 and in lighttp to 1024. We set both value to 65535 >> > > > or -1 and solve our problem. Now we have about 700Mbit per second >> > > > instead 70. >> > > >> > > Good catch. I wonder if there is any way to figure out the listen >> > > backlog (except using strace) for a socket, e.g. using a system level >> > > tool? >> > >> > Yes. The max listen backlog and the current listen backlog values >> > for listening sockets are available via Recv-Q and Send-Q fields >> > in 'netstat' and 'ss' output as well as tx_queue and rx_queue >> > under cat /proc/net/tcp >> > >> >> How do you get the max value reached, it seems to only give the >> current value, which is very instantaneous. > > max value refers to the value that is passed by the app as the > backlog parameter to the listen() call. >> hmm, actually I was looking for max queue length reached ... during the run of the listening program. Is there any such value available ? >> Also, is this the number of connections waiting to be accepted by the >> user program or the number of bytes on an already accepted connection >> not copied to the user program ? >> >> according to netstat man page: >> >> Recv-Q >> The count of bytes not copied by the user program connected to >> this socket. > > This description corresponds to an ESTABLISHED socket. Patches to > oveload these fields for listening sockets went in sometime last year, > but the man pages are not updated. patch to netstat ? so the /proc/...rx_queue should be ok to use to get this number ? or were there some additional values exposed by the kernel. Thanks -- Pranav > In case of a listening socket, Recv-Q indicates the current number of > pending connections waiting to be accepted and Send-Q indicates the > maximum length upto which the accept queue can grow(same as backlog > parameter to the listen() call). > > Thanks > Sridhar > > -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
